<P> The total number of military and civilian casualties in World War I was about 40 million: estimates range from 15 to 19 million deaths and about 23 million wounded military personnel, ranking it among the deadliest conflicts in human history . </P> <P> The total number of deaths includes from 9 to 11 million military personnel . The civilian death toll was about 8 million, including about 6 million due to war - related famine and disease . The Triple Entente (also known as the Allies) lost about 6 million military personnel while the Central Powers lost about 4 million . At least 2 million died from diseases and 6 million went missing, presumed dead . This article lists the casualties of the belligerent powers based on official published sources . About two - thirds of military deaths in World War I were in battle, unlike the conflicts that took place in the 19th century when the majority of deaths were due to disease . Nevertheless, disease, including the 1918 flu pandemic and deaths while held as prisoners of war, still caused about one third of total military deaths for all belligerents . </P>

How many casualties were there in world war 1