During the First World War, the Russian Red Cross Society (here in after referred to as the RRCS, Red Cross) took over the organization of the evacuation and treatment of mentally ill soldiers. The article covers the society’s involvement in organizing this type of specialized assistance on the Caucasian front, the region where, due to the underdevelopment of medicine, such help was especially relevant. In the early twentieth century, military psychiatry was just beginning to evolve, differentiating itself from psychiatry proper. The War Department had had no time to prepare medical institutions for the mentally ill. In the course of this research, based on previously unstudied documents from Russian and foreign archives, the author established how the psychiatric care of the army on the Caucasian front was organized, what difficulties the RRCS faced, and to what extent the organization was effective. This work was complicated by long distances in the theater of war, the lack of suitable premises for accommodating patients, and the lack of qualified specialists. Gradually, the RRCS created an extensive system of providing assistance to the mentally ill on the Caucasian front, which included flying psychiatric squads affiliated with the troops, taking patients from the army, evacuation points, distribution centers and rear infirmaries. In the course of its activities, the Red Cross worked closely with the local military administration and public organizations. The military district administration forbade the evacuation of the mentally ill from the Caucasus. Since there were not enough available medical institutions to accommodate the “chronic patients”, the organization was forced to discharge those who needed further treatment. In general, the RRCS played a significant role in the care of mentally ill soldiers on the Caucasian front, succeeding in the new direction of medicine. The expertise of the organization was appreciated by the local authorities who took over the administration of the region in 1917 and planned to use the staff, premises and inventory of the psychiatric hospitals of the RRCS aft er demobilization.