Background: Various reports have recently shown the efficacy of narrowband ul traviolet (UV) B phototherapy at 311 nm in the treatment of early stage mycosis fungoides (MF). Objectives: To examine the effectiveness and tolerability of mon ochromatic excimer light (MEL) at 308 nm as a first treatment for early stage MF (stage IA). Methods: Ten lesions from five patients with a clinical and histolo gical diagnosis of MF were treated with repeated applications of MEL until compl ete remission was achieved or up to a maximum of 10 applications, with a cumulat ive dose of 308 nm UVB of between 6 and 12 J cm- 2. All patients were observed every 2 weeks for 2 months, with a 1- year follow-up. Results: At present, al l patients are in complete remission, with no side-effects. Conclusions: Based on these results, MEL can be considered a useful tool in the treatment of early stage MF. Background: Various reports have recently shown the efficacy of narrowband ul traviolet (UV) B phototherapy at 311 nm in the treatment of early stage mycosis fungoides (MF). Objectives: To examine the effectiveness and tolerability of mon ochromatic excimer light (MEL) at 308 nm as a first treatment for early stage MF (stage IA). Methods: Ten lesions from five patients with a clinical and histolo gical diagnosis of MF were treated with repeated applications of MEL until compl retection was achieved or up to a maximum of 10 applications, with a cumulat ive dose of 308 nm UVB of between 6 and 12 J cm- 2. All patients were observed every 2 weeks for 2 months, with a 1-year follow-up. Results: At present, al l patients are in complete remission, with no side-effects. Conclusions: Based on these results, MEL can be considered a useful tool in the treatment of early stage MF.