When the Russian Empire entered World War I on 1 August 1914, Ragoza was still in command of the 19th Infantry Division. On 27 September 1914, Ragoza — by then a lieutenant general — became commander of the 25th Army Corps, a part of the 9th Army. He led the corps in the Battle of the Vistula River in September–October 1914. On 6 December 1914, he was promoted to general of the infantry. At the head of the 25th Army Corps, he distinguished himself during the battles of Vilkolaz and Urzhendov in late June 1915, when a counterattack by the corps defeated the Austro-Hungarian Army's 4th Army commanded by Archduke Joseph Ferdinand of Austria. He received the Order of Saint Vladimir Second Class with Swords, the Order of the White Eagle with Swords, and the Order of St. George Fourth Class.