Aim. To evaluate the efficiency of extracorporeal photopheresis (ECP) in the treatment of patients with refractory chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Subjects and methods. The study included 49 patients aged 2 to 55 years. Allo-HSCT was carried out in 38 (79%) patients with acute leukemias, 5 (10%) with chronic leukemias, 4 (8%) with myelodysplastic syndrome/myeloproliferative disease, and 2 (3%) with other hematologic diseases. The patients included in the study had glucocorticosteroid (GCS)-refractory disseminated cGVHD or a history of severe complications from GCS therapy. Results. When evaluating the efficiency of therapy, its response was recorded in 37 (77%) cases; the best results were obtained in patients with hepatic (82%), mucosal (76%), and skin (74%) lesions. The mean severity according to the cGVHD Working Group, National Institutes of Health, and a platelet level of more than 100·109/l were defined as factors improving a therapy response. In the patients receiving ECP, the overall survival was 70%. The latter was higher in the group of patients who had responded to ECP therapy without involving the gastrointestinal tract in the cGVHD process and in those receiving a combination of ECP and other immunosuppressive drugs. Conclusion. ECP is an effective treatment for patients with refractory cGVHD, it may be used in those with a history of severe complications from GCS therapy. ECP allows the dose of GCS to be reduced to the point of complete discontinuation.