BACKGROUND: A number of effective topical therapies are available for the treatment of tinea versicolor (TV). However, topical antifungals are difficult to apply to a large body surface area and for this reason TV is perhaps more easily treated with systemic agents. METHODS: A total of 128 patients with TV, aged 15-55 years, were entered into a randomized, double-blind, clinical trial comparing the efficacy and tolerance of two regimens of oral treatment for TV. The patients were randomly divided in two groups: group 1 received two 150 mg capsules of fluconazole in a single dose repeated weekly for 2 weeks; and group 2 received two 200 mg tablets of ketoconazole in a single dose repeated weekly for 2 weeks. Diagnosis of TV was made clinically by direct KOH preparation and Wood's lamp examination. RESULTS: Of 128 patients, 100 completed the study and no major side-effects were noted between the two treatment regimens. Results of the study showed no significant differences in efficacy, safety and tolerability between the two treatment regimens. The maximal cure rate was achieved at 8 weeks from the start of treatment and decreased slightly afterwards. CONCLUSIONS: Fluconazole and ketoconazole demonstrated similar efficacy in the treatment of TV. We also demonstrated a lack of correlation between mycological cure and hypopigmentation at the end of treatment (2 weeks) and the usefulness of Wood's lamp examination in detecting cure of TV.