Late immune dysregulation following allogeneic hematopoietic cell transplantation (HCT) is known as chronic graft-versus-host disease (GVHD), which is a major cause of mortality and morbidity after HCT, and a rise in its incidence is predicted. Better therapies are being sought to manage chronic GVHD and limit patients' exposure to corticosteroids. Extracorporeal photopheresis (ECP), an immune-modulating therapy, has shown preliminary safety and efficacy in treating chronic GVHD. However, access to ECP is limited, care is costly, and the optimal frequency, duration, and durability of response are unknown. Although nurses who care for patients with chronic GVHD recognize its adverse impact on patients' quality of life, limited evidence exists about the selection of patients most likely to benefit from ECP therapy and from the supportive care provided to them. A multidisciplinary approach is needed to define the desired outcomes of ECP therapy and to determine the evidence base for nursing management approaches.