Before the war, the Kingdom of Serbia had 4,500,000 inhabitants. According to the New York Times, in 1915 alone 150,000 people are estimated to have died during the worst typhus epidemic in world history. With the aid of the American Red Cross and 44 foreign governments, the outbreak was brought under control by the end of the year. The number of civilian deaths is estimated by some sources at 650,000, primarily due to the typhus outbreak and famine, but also direct clashes with the occupiers Serbia’s casualties accounted for 8% of the total Entente military deaths. 58% of the regular Serbian Army (420,000 strong) perished during the conflict. The total number of casualties is placed around 1,000,000: 25% of Serbia’s prewar size, and an absolute majority (57%) of its overall male population. L.A. Times and N.Y. Times also cited over 1,000,000 victims in their respective articles.
The extent of the Serbian demographic disaster can be illustrated by the statement of the Bulgarian Prime Minister Vasil Radoslavov: “Serbia ceased to exist” (New York Times, summer 1917). In July 1918 the US Secretary of State Robert Lansing urged the Americans of all religions to pray for Serbia in their respective churches.
Serbia suffered enormous casualties. The Serbian Army had been largely destroyed towards the end of the war, falling from about 420,000 at its peak to about 100,000 at the moment of liberation.
The Kingdom of Serbia lost 1,100,000 inhabitants during the war (both army and civilian losses: of 4.5 million people, 275,000 were military deaths, while 450,000 were civilian – mostly due to food shortages, epidemics and the Spanish flu—and there were 133,148 wounded), which represented over 15% of its overall population. According to the Yugoslav government in 1924, Serbia lost 365,164 soldiers, or 26%, of all mobilized personnel, while France suffered 16.8%, Germany 15.4%, Russia 11.5%, and Italy 10.3%.
At the end of the war, there were 114,000 disabled soldiers and 500,000 orphaned children.