BACKGROUND: In recent years, narrow-band ultraviolet B (NB-UVB, 311-313 nm) has been found to be beneficial for early-stages mycosis fungoides (MF). The aim of this study is to investigate the effect of NB-UVB in 20 patients with early-stage MF. METHODS: Twenty patients (10 women and 10 men, mean age 54 +/- 22 years) with clinically and histologically confirmed MF were enrolled in the study. All of the patients had clinical stage I disease (T1 or T2, N0, M0) with cutaneous involvement, consisting of patch-stage disease of limited extent, in 50% of the cases (stage IA), and more widespread in the other 50% (stage IB). All the patients were treated with NB-UVB therapy until more than 95% clearance of the patient's skin lesions had occurred. RESULTS: A complete response was achieved in 90% of the cases after a mean of 29 +/- 14 treatments within a mean period of 4 months (range 1-8 months), with an average cumulative dose of 25 +/- 16.77 J/cm(2). In the follow-up period, relapse occurred after a mean period of 8 months (range 3-17 months), and then therapy was restarted. CONCLUSION: This study provides evidence that NB-UVB might be an efficient option for stage IA and IB MF patients.