Photopheresis (extracorporeal photochemotherapy, ECP) is a new type of photochemotherapy used for the treatment of oncological and autoimmune diseases. Additionally, recent reports indicate that this therapy is promising in both pediatric and adult patients who develop graft versus host disease (GVHD) resistant to conventional protocols after bone marrow transplantation (BMT). In this paper, we review 31 studies where ECP was used in the treatment of acute and chronic GVHD. A total of 76 (32% female) acute GVHD patients have been considered in 11 series. Fifty-nine patients presented with skin involvement; 47 had liver involvement, and 28 had gastrointestinal manifestations. Treatment duration ranged from 1 to 24 months. A regression of skin manifestations was observed in 83% of the patients with a complete response in 67%. A complete regression of liver and gut manifestations was reported in 38% and 54% of the patients, respectively. The overall patient survival was 53%. Of the 43 patients alive, 8 developed chronic GVHD manifestations. The immunosuppressive therapy was discontinued in 28% of cases and reduced in 46%. A total of 204 (45% female) chronic GVHD patients treated with ECP 1 to 110 months from transplantation have been considered in 20 series. One hundred twenty-eight patients presented with skin involvement, 84 with liver, 31 with lung, and 59 with oral manifestations. Treatment duration ranged from 3 to 40 months. A regression of skin manifestations was observed in 76% of patients with a complete response in 38%. An improvement of liver and lung involvement was reported in 48% and 39% of the patients, respectively. Of the 59 patients with oral manifestations, an improvement was obtained in 63% of cases. The overall patient survival was 79%. ECP is a nonaggressive treatment that may benefit patients with both acute and chronic GVHD who do not respond to standard immunosuppressive therapy.