Despite the growing availability of improved immunosuppressive agents, acute and chronic rejection episodes remain a major complication in heart transplant recipients. The rejection of allografts is a normal part of the body's response to foreign antigens. The key to controlling this response is to administer a regimen of multiple immunosuppressive drugs. Evidence indicates that by adding extracorporeal photochemotherapy to a standard immunomodulatory regimen, the rejection process can be reversed without significantly increasing patient risk. In this case study we examine extracorporeal photochemotherapy and the care of patients receiving this therapy.