8.5 million.
Estimates vary, but around 10 million (10,000,000) soldiers of all belligerents lost their lives in the First World War. (About another 9 million civilians died.)
Several answers have been added for this question, but note that the question asks specifically about military deaths. (All figures given here are necessarily approximate since record keeping in 1918 was not as precise as now.)
It's estimated at about 117,000 deaths
World War I
It is not really possible to tell the last soldier who died at the end of the World War 1.
World War II.
world war 1.
World War 1
58000
620,000
He died in the Second Punic War, when a Roman soldier attacked him. There are many different cases, on what he did when the soldier killed him.
5,573 men from California died in the war.
217,600 French Soldiers were killed during World War 2. This includes French Colonies.
Korea was a Japanese Colony during World War 2. There is o recorded Military deaths of any Korean Soldier but 450,000 Civilians were killed during World War 2.