BACKGROUND Mycosis fungoides (MF) is a non-Hodgkin's T-cell lymphoma of the skin that often begins as limited patches and plaques with slow progression to systemic involvement. No studies have been published comparing photochemotherapy (PUVA) with other topical therapies in the treatment of early-stage disease. OBJECTIVE The purpose of the study was to examine our long-term experience using PUVA to treat early-stage MF and to compare its effectiveness and side-effect profile with other previously reported topical therapies. METHODS Eighty-two patients with MF (83% stage IA or IB) were treated with PUVA. Clinical and histologic features were observed for a period from 2 months to 15 years (median, 43 months). RESULTS A response was noted in 78 patients (95%) with complete clinical and histologic clearing in 53 patients (65%) for all stages. The mean duration of total complete response to PUVA for all stages was 43 months (3.6 years). The mean survival of our study group for all stages was 8.5 years. Signs of chronic actinic skin damage were found in 10% of patients, including three patients with basal cell carcinomas and three patients with squamous cell carcinomas. In a nonrandomized comparison with previously reported data for other topical therapies, the efficacy and side-effect profile of PUVA compared favorably. CONCLUSIONS PUVA is an effective and safe therapy for MF with prolonged disease-free remissions being achieved. Patients with stage I and II MF respond best to PUVA. Palliative therapy with PUVA is useful in more advanced cases of MF.