In the following years, he participated in Russo-Japanese War, in which he commanded the 2nd Manchurian Army. He participated in the battles at Sandepu and Mukden. In the war, he was noticed by fellow officers as one of the best generals and valuable workers in the army. While retreating from Mukden, General Ruzsky was in the rear of the army and was injured from falling off a horse, but he remained in the army.