The Russo-Japanese War (1904-1905) was the apogee of bilateral tensions between Russia and Japan in the Far East in the late 19th and early 20th centuries. Just over 2,000 people were captured by the Russians. It should be noted that not all prisoners of war were ethnic Japanese: Chinese, Koreans, Europeans, and Americans were also captured by the Russians. Despite the fact that most of the prisoners were Japanese military personnel, there were also representatives of civilian professions in captivity. The paper provides an analysis of the composition of prisoners of war. It is concluded that most of the prisoners were ethnic Japanese, the rest were representatives of other nationalities. It seems interesting to trace the circumstances of the surrender of the above-described ethnic groups, as well as their professional affiliation.