Management of tinea pedis in patients who have the human immunodeficiency virus (HIV) is problematic; in those patients, dermatophytoses may be more difficult to treat than in the general population. This prospective, open-label, multicenter, randomized study evaluated the efficacy and safety of a short course of oral terbinafine for tinea pedis in patients who are HIV positive. Twenty-seven patients were randomized to receive oral terbinafine 250 mg once daily for 2 or 4 weeks; 17 patients with positive initial cultures and follow-up cultures were evaluable for efficacy at week 8. Mycological cure (defined as negative potassium hydroxide [KOH] microscopy and culture results) occurred in 47% (8) of patients; and modified mycological cure (defined as negative follow-up cultures) occurred in 65% (11) of patients. All 27 patients were evaluated for safety. Clinical cure (defined as minimal residual signs and symptoms) occurred in 82% (14) of patients. Oral terbinafine was well tolerated, indicating that regimens of 2 or 4 weeks are safe and effective for the treatment of tinea pedis in patients who are HIV positive.