Background: Extracorporeal photochemotherapy (ECP; photopheresis) is a treatment option for cutaneous T-cell lymphoma (CTCL). Objective: This study describes the outcomes obtained with ECP alone or with adjuvant therapy in treating CTCL. Methods: A 9-year retrospective study was performed at a single institution. Results: Among 69 patients, 37 were treated with 6 months or more of ECP alone over an average of 36.9 months. Of these patients, 68% (25/37) had stage T2, 5% (2/37) had stage T3, and 27% (10/37) had stage T4 CTCL. Complete response (no skin or systemic disease for 1 month or more) and partial response (50%-99% skin improvement for 1 month or more) were achieved by 14% (5/37) and 41% (15/37) of patients, respectively, giving an overall response rate of 54% (20/37). In recalcitrant patients, adjuvant therapy significantly increased the response rate from 31% (4/13) to 69% (9/13) (P = 0.004). ECP was well tolerated in the entire patient population. Conclusion: Response rates in this study compared favorably with those in previous studies, underscoring the potential value of ECP in treating CTCL. To our knowledge, this investigation included the largest group of CTCL patients ever treated with ECP at a single institution. (J Am Acad Dermatol 2000;43:263-71.)