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The Top 10 Deadliest Wars in History

Larry Slawson received his Master's Degree in History from UNC Charlotte in 2018. He specializes in American and European History.

From the Second World War to the An Lushan Rebellion, this article ranks the 10 worst (and deadliest) conflicts in history.

From the Second World War to the An Lushan Rebellion, this article ranks the 10 worst (and deadliest) conflicts in history.

The Destructive Costs of War

Throughout world history, countless wars have been fought around the globe over issues ranging from religious differences, territorial disputes, politics, and ethnicity. While war, in itself, is always destructive (and costly), there exists a handful of wars in history that have proven quite devastating in regard to both deaths and overall destruction. This work examines the top 10 deadliest wars in human history. It provides an analysis of each conflict’s origins, overall death toll, and casualties (war-related injuries) in regard to both the military and civilian sectors. It is this author’s hope that a better understanding of the destructive capacity of war will accompany readers following their completion of this work.

John F. Kennedy Quote

"War will exist until that distant day when the conscientious objector enjoys the same reputation and prestige that the warrior does today."

— John F. Kennedy

The Top 10 Deadliest Wars in History

  • The Thirty Years' War
  • Chinese Civil War
  • Russian Civil War
  • The Dungan Revolt
  • First World War (WWI)
  • Taiping Rebellion
  • The Qing Conquest of the Ming Dynasty
  • Second Sino-Japanese War
  • An Lushan Rebellion
  • Second World War (WWII)
Artist's rendition of the "Battle of Breitenfeld" (1631). This was a major conflict during the Thirty Years' War.

Artist's rendition of the "Battle of Breitenfeld" (1631). This was a major conflict during the Thirty Years' War.

10. Thirty Years' War

The Thirty Years’ War was a conflict fought in Central Europe between 1618 and 1648 among the European powers of the day. Although the war originally began as a conflict between Protestant and Catholic states from the disintegrating Holy Roman Empire, it quickly spread in the years that followed to encompass much of the European continent. Deploying large armies (including a large contingency of mercenary fighters), countless individuals perished in the years that followed, making the Thirty Years’ War one of the bloodiest conflicts in human history.

In addition to its religious origins, the Thirty Years’ War continued to expand in Central Europe due to the dynastic and territorial rivalries that were prevalent during this era. Political leaders—who viewed the conflict as an opportunity to reshape the European continent in a manner that favored their own interests—poured countless resources into the war, with disastrous consequences. By the time peace was finally brokered with the Treaty of Westphalia in 1648, Europe and its traditional boundaries would never be the same again.

How Many People Died During the Thirty Years’ War?

Although particular regions of Europe suffered more than others, it is estimated that nearly eight million individuals were killed as a result of the Thirty Years’ War, with countless others wounded. Due to the immense destruction caused by the conflict, disease also played a tremendous role in the number of individuals that died (both civilians and soldiers, alike). Bubonic Plague, dysentery, and typhus all reached epidemic levels during this time period, with many German and Italian communities hit hardest of all. Making matters worse, many of the wartime powers also suffered bankruptcy as a result of the conflict, leaving the cleanup and rebuilding of Europe nearly impossible to achieve in the years that followed. For these reasons, the Thirty Years’ War remains one of the deadliest and bloodiest conflicts of human history.

Photo of Chiang Kai-shek (left) and Mao Zedong (right); the two major leaders of the Chinese Civil War.

Photo of Chiang Kai-shek (left) and Mao Zedong (right); the two major leaders of the Chinese Civil War.

9. Chinese Civil War

The Chinese Civil War was a conflict fought in China during the mid-Twentieth Century between Communist forces and the Republic of China. Occurring in two separate phases (due to the onset of World War II), the first phase of the Chinese Civil War occurred between 1927 and 1936, with the second phase occurring around 1946 and 1950. The conflict erupted following the collapse of the Qing Dynasty. As government and communist forces attempted to seize power in the power vacuum that followed, conflict ensued soon after with devastating results.

To make matters worse, political and military aid from abroad (from the Soviet Union, in particular) deepened hostilities further between communists and nationalists, as both sides began an active campaign to eradicate the other. Although hostilities came to a halt with the onset of the Second World War and the invasion of China by the Japanese Empire, military unrest once again ensued with the conclusion of the war as the Kuomintang and Communist forces took to the streets to resume the fighting. Although the Communists (led by future leader, Mao Zedong) eventually won out, the costs (in regard to human lives) were tremendous for the Chinese people by the end of the civil war.

How Many People Died in the Chinese Civil War?

In total, it is estimated that nearly 8 million people (both military personnel and civilians) died as a result of the Chinese Civil War. Many of these deaths are often attributed to the mass atrocities and genocides perpetuated by both Communist and Kuomintang forces during the duration of the war. Nevertheless, overall losses incurred from regular fighting were also extraordinarily high and are estimated at nearly two million dead and wounded. In terms of dead and wounded, the overall numbers increase exponentially, with an estimated 15.5 million casualties in total. Despite these extraordinary losses, the introduction of Communism into China only extended the suffering of the Chinese people as Mao’s Great Leap Forward resulted in the death of millions of his own people in the decades that followed.

Photo of the Red Army marching through the streets of Moscow during the Russian Civil War.

Photo of the Red Army marching through the streets of Moscow during the Russian Civil War.

8. The Russian Civil War

The Russian Civil War was a multi-party war fought between 1917 and 1926 which involved both the Red Army (communist) and White Army (nationalist) forces. Following the collapse of the Russian Empire and the dissolution of Tsar Nicholas II’s power, Bolshevik forces led by Vladimir Lenin engaged nationalist troops for control of the Russian interior with disastrous consequences in terms of lives lost and property destroyed. Lasting approximately six years, the bloody war pitted Russian against Russian as numerous skirmishes and battles erupted across the country’s interior. Despite horrendous losses on all sides of the conflict, the cessation of hostilities would ultimately prove short-lived, however, as the victorious Communist regime immediately ushered in an era of terror and repression in the decades that followed.

How Many People Died in the Russian Civil War?

Total death figures for the Russian Civil War are difficult to ascertain as the conflict occurred during a chaotic time in Russian history that involved the radical transfer of power from Tsar to revolutionary forces. Nevertheless, it is currently accepted by historians that the conflict claimed approximately nine million lives, with several million more maimed or seriously wounded by the war.

Although not counted in the official death toll, millions more are known to have perished from circumstances caused by the war (such as famine, epidemics, and starvation). Ukraine, in particular, is estimated to have lost nearly two million people from famine, disease, and repressive measures carried out by the Communist regime between 1921 and 1923 (

Portrait of Yaqub Bek; a major leader of the Dungan Revolt.

Portrait of Yaqub Bek; a major leader of the Dungan Revolt.

7. The Dungan Revolt

The Dungan Revolt (or Hui Minorities War) refers to a religious conflict fought in Western China between 1862 to 1877. The war began when Hui Muslims began rioting in China in response to religious and racial discrimination that was being perpetuated by the Qing Dynasty. In response to the riots, the Qing government retaliated with astonishing speed, unleashing devastating reprisals and massacres against Hui Muslims across Western China. As conflict ensued, the Hui Rebels were both outmatched and outgunned by their adversaries, as the Qing government enacted a campaign of “total war” against both rebels and Muslim civilians.

Although the Hui Rebels fought heroically for several years, their lack of coordination, leadership, and organization ultimately led to their downfall as Hui Muslims found it difficult to lead coordinated attacks on the Qing army.

How Many People Died During the Dungan Revolt?

Due to China’s large population figures and the chaotic situation on the ground in 1862 within the region, current death tolls for the Dungan Revolt are difficult to ascertain by scholars. However, currently accepted estimates place overall deaths in the vicinity of 10 million, with millions of other civilians, rebels, and soldiers wounded by the conflict. These numbers may be far higher though, as various reprisals against the Hui Rebels were carried out by the Qing Dynasty in the years that followed. As a result, overall death figures could potentially be as high as 20 million.

The infamous trenches of World War I.

The infamous trenches of World War I.

6. First World War

The First World War, also known as the “Great War,” was a worldwide conflict that originated in Europe on 28 July 1914. Lasting four years, the war resulted in the mobilization of approximately 70 million military personnel as the European continent was engulfed by conflict in nearly every corner of the map. When the fighting finally ceased in November 1918, Europe faced devastation on a scale never before seen in history as the continent experienced widespread political, social, economic, and cultural changes in the conflict’s wake.

How Many People Died in the First World War?

In total, approximately nine million military personnel lost their lives during the Great War with an additional 9 to 10 million civilians killed. Scholars attribute these tremendous death tolls to advances in technology; most notably, the arrival of the machine gun, chemical weapons, and the advent of airplanes.

In addition to the 18 million individuals that perished as a result of the war, scholars are quick to point out that revolutions, genocides, and epidemics (caused by the war during the years and decades that followed) resulted in tremendous death tolls as well. While these deaths are not included in the overall figures for the First World War, scholars estimate that epidemics and genocides, alone, may account for an additional 50 to 100 million lives. To this day, the Great War remains one of the deadliest conflicts in human history.

Pictured above is Hong Xiuquan, who served as leader of the Taiping rebels.

Pictured above is Hong Xiuquan, who served as leader of the Taiping rebels.

5. Taiping Rebellion

The Taiping Rebellion (or Taiping Civil War) refers to a civil war that took place in China between 1850 and 1864 between the Qing government and Taiping Heavenly Kingdom. Led by an individual named Hong Xiuquan (who believed he was the brother of Jesus Christ), the Taiping forces waged a nationalist, political, and religious war against the Qing Dynasty with the goal of converting the Chinese people to Christianity (and toppling the Qing government in the process). Based in modern-day Nanjing, the Taiping rebels managed to take control of significant portions of South China with an estimated 30 million people falling under their control at the height of their power.

Although the Taiping rebels saw success during the first decade of their campaign, an attempted coup (coupled with their failure to capture China’s capital city of Beijing) ultimately led to their downfall. As their own forces began to fragment (due to the breakdown of a centralized command structure), militia armies (most notably the Xiang Army) were quickly mobilized against the Taiping Rebels. Within two years, the Xiang Army had pushed the Taiping Rebels all the way to their capital of Nanjing, capturing the city in June 1964.

How Many People Died During the Taiping Rebellion?

Estimated deaths from the Taiping Rebellion are difficult to measure due to the lack of official records from this time period. However, most estimates place the number of dead at approximately 20 to 30 million, with thousands of others wounded. To this day, the Taiping Rebellion is considered one of the deadliest civil wars in human history, as well as the largest conflict of the Nineteenth Century.

Artistic depiction of the Battle for Ningyuan; a major conflict during the Qing-Ming Transition.

Artistic depiction of the Battle for Ningyuan; a major conflict during the Qing-Ming Transition.

4. The Qing Conquest of the Ming Dynasty

The Qing Conquest of the Ming Dynasty, also known as the “Ming-Qing Transition” or “Manchu Conquest of China,” refers to a decades-long war between the Qing and Ming Dynasty that lasted from 1618 to 1683. Originating from a series of complaints known as the “Seven Grievances,” which enumerated the major social and political issues facing China at this time, rebel groups (alongside bands of peasants) waged war against the ruling Ming Dynasty with the hope of achieving reform.

Lasting nearly 70 years, city after city fell to the rebels with large swathes of Ming officers and government officials defecting to the rebel cause (once it was apparent that victory was futile). Through their common front against the Ming, rebel groups coalesced to form the Qing Dynasty in 1644, installing Hong Taiji as their first emperor. However, victory would not be achieved until nearly 40 years later, as pockets of resistance from Ming sympathizers continued to flourish in the south; leading to brutal fighting for several decades.

How Many People Died as a Result of the Qing Conquest?

As with most conflicts from this time period, overall fatalities are difficult to ascertain due to the tremendous social, political, and economic upheaval created by the conflict (and transition). Generally speaking, however, it is currently estimated that nearly 25 million people died as a result of the war, with millions of additional people maimed and scarred from the countless battles. Following the war, tens of thousands may have also perished due to military reprisals carried out against Ming loyalists. This includes both military personnel and civilians. Nevertheless, exact fatalities are impossible to determine with accuracy. To this day, the Qing Conquest of the Ming Dynasty is considered one of the deadliest conflicts in human history, and certainly the largest of the Seventeenth Century.

Japanese forces attacking Shanghai in November 1937.

Japanese forces attacking Shanghai in November 1937.

3. Second Sino-Japanese War

The Second Sino-Japanese War refers to a conflict between the Republic of China and the Empire of Japan. Lasting from 7 July 1937 to 2 September 1945, the war is widely considered one of the bloodiest conflicts in human history as Japanese forces raped, pillaged, and killed countless Chinese civilians and military personnel in their quest for victory.

The conflict began as a result of the Japanese Empire seeking to expand its control (and influence) into the heart of Asia where resources, labor, and food were plentiful for their growing empire. Using an incident near the Marco Polo Bridge in Wanping as an excuse to invade, Japanese forces quickly overwhelmed Chinese forces in July 1937 with approximately half a million troops. Although the Chinese fought valiantly against the Japanese until the end of 1945 (the conclusion of World War II), Japan initiated a murderous and repressive system of control that effectively brought the country to its knees.

How Many People Died During the Second Sino-Japanese War?

Although figures vary significantly (depending on the source), it is generally accepted that nearly 29 million people died as a result of the Second Sino-Japanese War. Of these fatalities, it is believed that approximately 20 to 25 million were civilians, with an estimated four to five million military personnel killed on both the Chinese and Japanese sides. These figures are alarming, as they illustrate the sheer brutality and murderous intent of the Japanese forces in their occupation.

Countless memoirs detail the tremendous violence carried out against Chinese civilians who were dubbed “subhuman” by the Japanese military. Mass executions, widespread rape, and deliberate starvation were only a few of the atrocities committed. In the “Rape of Nanking,” alone, it is estimated that nearly 300,000 Chinese civilians were killed, with an additional 20,000 women raped by Japanese troops. For these reasons, the Second Sino-Japanese War is widely considered one of the bloodiest conflicts in world history.

Portrait of General An Lushan; a major instigator of the "An Lushan Rebellion."

Portrait of General An Lushan; a major instigator of the "An Lushan Rebellion."

2. An Lushan Rebellion

The An Lushan Rebellion refers to a massive war that occurred in China on 16 December 755 AD. Lasting nearly eight years, the rebellion was a direct result of General An Lushan declaring himself emperor of Northern China in defiance of the established Tang Dynasty. Fearing that their reign was close to an end, the Tang Dynasty hired nearly 4,000 mercenaries to accompany their army in the battles that ensued. Spanning the reign of three separate emperors, the war resulted in tremendous social, economic, and political upheaval within China before the rebellion was finally crushed in 763 AD.

How Many People Died as a Result of the An Lushan Rebellion?

Overall death tolls for the An Lushan Rebellion are difficult to measure given the chaotic social and political situation that resulted from the upheaval of various populations in the region. And while fatalities from combat were certainly heavy for both sides of the conflict, historians are forced to account for deaths caused by the economic destruction that resulted from large-scale battles. Destruction of crops and various food sources, alone, resulted in mass starvation and disease throughout the civilian sectors of China as the war reached its apex. Generally speaking, however, census comparisons from before and after the rebellion indicate a dramatic population drop for much of China. In total, scholars have placed overall deaths (for both military and civilians) at an astounding 36 million people.

Historians are quick to point out, however, that actual fatality rates are likely far different as mass immigration abroad could have skewed these numbers dramatically. Nevertheless, the An Lushan Rebellion continues to be viewed as one of the most destructive and bloody conflicts in human history.

Photo of German soldiers preparing to advance against a fortified Soviet position.

Photo of German soldiers preparing to advance against a fortified Soviet position.

1. Second World War

The Second World War (or World War II) refers to a massive global conflict that lasted from 1939 to 1945, and which involved nearly all of the world’s countries. Divided into two separate camps (the Axis vs. the Allies), the two military alliances engaged in total war for nearly six years with devastating consequences in terms of both death and destruction. In total, an estimated 100 million military personnel from approximately thirty different countries were thrust into the conflict with horrific consequences. The conflict left in its wake thousands of destroyed cities and millions of lost lives.

How Many People Died During World War II?

In total, it is generally accepted by scholars that approximately 70 million people died as a result of the Second World War. Of these, nearly 20 million people were military personnel, while another 40 to 50 million are believed to have been civilians. The Soviet Union, alone, accounts for nearly 27 million of these deaths as the war devastated large swathes of Eastern Europe for the duration of the war.

Although fighting was fierce on both sides of the conflict, scholars are quick to point out that the majority of deaths were caused by disease, starvation, bombings, and massacres of the civilian population. Deliberate genocides were also carried out against numerous ethnic groups during the war, resulting in tremendous casualties. Jews alone account for nearly six million deaths due to the genocidal practices of the Nazi regime during a period known as the Holocaust. For these reasons, World War II is considered the bloodiest and costliest war in human history as the conflict devastated the European, Asian, and African continents for decades to come.

Concluding Thoughts

In closing, war continues to be a horrible reality for much of the world. Ethnic tensions, religious differences, and political ideologies all provide an unlimited source of animosity (and hatred) that too often spills over into conflict. With the advent of the nuclear age and the development of WMDs (weapons of mass-destruction), war’s devastating potential has never been stronger in world history. If history once again repeats itself in the form of a worldwide conflict, the results could be catastrophic. For the sake of us all, let us hope this never occurs.

Works Cited


  • Chang, Iris. The Rape of Nanking: The Forgotten Holocaust of World War II. New York, New York: Penguin Books, 1997.
  • Figes, Orlando. A People’s Tragedy: A History of the Russian Revolution. New York, New York: Viking, 1996.
  • Marples, David. Russia in the Twentieth Century: The Quest for Stability. New York, New York: Taylor & Francis, 2011.
  • Roberts, J. A. G. A History of China 2nd Edition. New York, New York: Palgrave MacMillan, 2006.


  • Wikimedia Commons

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2020 Larry Slawson


Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on June 14, 2020:

I hope the author take that into account in his next edit.

MG Singh emge from Singapore on June 13, 2020:

This is a fascinating article and very well presented. I would like the campaigns of Mohammed Ghazni to be included but then it's a personal choice.

Larry Slawson (author) from North Carolina on June 13, 2020:

Thank you, Arthur! So glad you enjoyed! That's a really interesting point, for sure. I hadn't thought about that until now, but its true. Conflict for thousands of years, and now suddenly there is peace. That would certainly have a major impact on societal development.

Arthur Russ from England on May 29, 2020:

Thanks for an interesting read. From an historical view point it’s a topic of interest to me, not only because of my interest in genealogy but also because historically Europe has been almost constantly at war with itself for over 2,000 years; it’s only in the past 70 years, since the formation of the EU, that we finally have ‘peace in our time’ across Europe. So as a European, the countless wars England has had with its neighbours over the millennia have had a profound effect on our Society and Culture.

But as you say, “for the sake of us all, let’s hope worldwide conflict” can be assigned to the history books and never rear its ugly head again.

Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on April 30, 2020:

Larry, every sane person will tell you that war is bad. But the military, because they were trained to fight, will gladly welcomed war. It is actually they bread and butter. It is they life. Have you noticed that those who make the decision for the war were in certain cases actually ex-war lords? Thanks.

Larry Slawson (author) from North Carolina on April 30, 2020:

Thank you, Pamela! Yes, the Russians were definitely ruthless! Historians still don't know how many individuals perished under Stalin once the war ended.

Pamela Oglesby from Sunny Florida on April 30, 2020:

Larry, You would think the world would have learned some lessons yet it seems we are always fighting somewhere. I was not surprised that WWII had the most deaths.

It seems like Russia was sure ruthless for what they did against the people even after the war. This was an interesting article.