Background: Early-stagemycosis fungoides(IA, IB, IIA) (MF) has long been treated with various agents including topical potent steroids, nitrogenmustard, carmustine, oral psoralen plus UVA (PUVA)broadband UVB, electron-beam radiotherapy, interferon-αand retinoids. However, each of these modalities is associated with various side-effects. Narrowband UVB (NBUVB) therapy has the same effect but is safer to use than the other methods. Objective: Our purpose in this prospective study was to determine the effects of NB-UVB in early-stage MF both clinically and histopathologically. Materials andmethods: Twenty-three patients (20 men, three women, aged 27-78 years) with clinically and histologically confirmed MF were enrolled. Patients received NB-UVB therapy three times a week. Clinical and histological responses, cumulative doses, total number of treatments, side-effects and duration of remission period were noted. Results: Six patients had stage IA MF, 15 patients stage IB and two patients stage IIA. Eighteen patients had patch stage and five patients had plaque stage histopathologically. All of the patients in the patch group had a complete response (CR). In the plaque group, three patients (60%) had a CR and two (40%) had partial (PR) or no clinical response (NR). The clinical response between patch and plaque groups was statistically significant. Regarding the histopathological findings, 17 (94.4%) had complete clearing and only one (5.6%) patient had a partial improvement in the patch group. In the plaque group, one (20%) patient had complete clearing and four (80%) patients had partial or no improvement. The difference between the two groups was statistically significant. In the patch group, the mean cumulative dose was 90.15 J/cm2 and the mean number of treatments was 35.33. In the plaque group, themean cumulative dosewas 90.67 J/cm2 and themean total number of treatments was 39.40. The differenceswere not statistically significant, either between the mean cumulative dose or the mean number of treatments. The mean duration of follow-up was 10.87 months (range 1-25 months). Only one of the patients had a relapse. Conclusions: NB-UVB therapy for patients with early-stage MF is an effective and safe treatment with the effect lasting for months. We suggest that clinical clearance correlates with histological improvement except for patients in the plaque stage. Background: Early-stagemycosis fungoides (IA, IB, IIA) (MF) has long been treated with various agents including topical potent steroids, nitrogenmustard, carmustine, oral psoralen plus UVA (PUVA)broadband UVB, electron-beam radiotherapy, interferon-αand Objective: Our purpose in this prospective study was associated with various side-effects. NB-UVB in early-stage MF both clinically and histopathologically. Materials and methods: Twenty-three patients (20 men, three women, aged 27-78 years) with clinically and histologically confirmed MF were enrolled. Patients received NB-UVB therapy three times a week. Clinical and histological responses, cumulative doses, total number of treatments, side-effects and duration of remission period were noted. Results: Six patients had stage IA MF, 15 patients stage IB and two patients Stage IIA. Eighteen patients had patch stage and five patients had a plaque stage histopathologically. All of the patients in the patch group had a complete response (CR). In the plaque group, three patients (60%) had a CR and two (40 %) had partial (PR) or no clinical response (NR). The clinical response between patch and plaque groups was also ly negative. Regarding the histopathological findings, 17 (94.4%) had complete clearing and only one (5.6%) patient had a Partial improvement in the patch group. In the plaque group, one (20%) patient had complete clearing and four (80%) patients had partial or no improvement. The difference between the two groups was in lyotropic or significant. In the patch group, the The mean cumulative dose was 90.15 J/cm2 and the mean number of treatments was 35.33. In the plaque group, themean cumulative dosewas 90.67 J/cm2 and themean total number of treatments was 39.40. The differences were not ascended ly significant, either between the mean cumulati ve dose or the mean number of treatments. The mean duration of follow-up was 10.87 months (range 1-25 months). Only one of the patients had a relapse. Conclusions: NB-UVB therapy for patients with early-stage MF is An effective and safe treatment with the effect lasting for months. We suggest that clinical clearance correlates with histological improvement except for patients in the plaque stage.