In 1916, after Romania entered the conflict, Tonitza was drafted into the Army and fought from 20 to 25 August with the 84th Infantry Regiment at the Battle of Turtucaia. Wounded, he fell prisoner to the Bulgarians, and was sent to an internment camp in Kardzhali, together with fellow painter and the sculptor Horia Boambă. There, he became ill with malaria and rheumatism, which would plague him until his death. For his valor in battle, Tonitza was awarded in November 1916 the Order of Michael the Brave, 3rd class. He was set free and returned in April 1918.