Background: Tinea versicolor is a common superficial mycosis, which is caused by lipophilic yeasts, malessezia furfur. It is a chronic and recurrent skin disease. It occurs most commonly in young post-pubertal people and in hot and humid climates (North and south provinces of Iran). Objective: Comparison of effects of ketoconazole 2% shampoo (Shafa Lab) with selenium sulfide 2.5% shampoo on tinea versicolor. Patients and Methods: Two-hundred patients with tinea versicolor were divided in 2 groups, each consisted of 10 patients, one group was treated with ketoconazole 2% shampoo and the other one with selenium sulfide 2.5% shampoo. Results: We found out that ketoconazole 2% shampoo was more effective (89% cure rate) than selenium sulfide 2.5% shampoo (35% cure rate). Conclusion: It seems that ketoconazole 2% shampoo is more effective than selenium sulfide 2.5% shampoo in the treatment of tinea versicolor.