With the start of the World War I in 1914, Burdenko once again volunteered for the frontline and joined the Red Cross detachment of the Northwestern Front, taking part in the East Prussian Operation and the Battle of the Vistula River. In addition to the duties of field surgeon he also evacuated wounded soldiers under hostile fire, organized triage, aid and dressing stations, including special sections for soldiers with stomach, lungs and skull wounds. For the first time in battlefield medicine Burdenko applied first aid care for skull injuries. From 1915 to 1917, he also worked as a consultant surgeon, first at the Kovno and Vilna Governorates, then at the 2nd Army and various Riga hospitals. In March 1917, he was appointed the Main Battlefield Medical Inspector, but left the post on May due to disagreements with the Russian Provisional Government and returned to front.