After the outbreak of World War I, he headed the 1st Caucasus Cossack Corps on the Caucasus Front and was prominent at the Battle of Sarikamish. During the Persian Campaign Baratov was successful in defeating Kerim Pasha's rear troops on August 5, 1915 after the Battle of Kara Killisse. His task was to counter the pro-German forces in Persia (headed by Georg von Kanitz), and to link Russian forces with the British expeditionary forces in Persia. In October 1915, he landed at Bandar-e Anzali and by December 3, 1915, took the ancient Persian capital of Hamadan. With the occupation of Qom and Kermanshah, the Russian forces under Baratov effectively isolated Persia from Ottoman Turkey, thus securing Persia for the Entente Powers. Baratov was decorated with the Order of St. George of the Fourth degree in October, 1916. After returning to Russia on March 24, 1917, he commanded the Caucasus Military District. On May 25, 1917 was appointed commander of the 5th Caucasus Army Corps. However, after the British defeat at the Siege of Kut, the Turks launched a massive offensive, forcing Baratov to return to Persia. He was made a general of cavalry on September 8, 1917.