Background: Tinea corporis treatment usually requires topical application of an antifungal agent for 2 to 3 weeks. Objective: We evaluated short-term treatment of tinea corporis with butenafine hydrochloride, a new benzylamine with in vitro fungicidal activity. Methods: Patients (n = 78) were randomly selected to apply butenafine or its cream vehicle alone once daily for 14 days and were periodically assessed until day 42. Results: Butenafine recipients had significantly higher rates of mycologic cure beginning at day 7 (64% vs 9%) with continued improvements through day 42 (88% vs 17%). They also had higher rates of effective treatment (mycologic cure and 90% to 100% symptom improvement) at day 7 (33% vs 0%) with increasing rates through day 42 (81% vs 14%). Conclusion: Butenafine provides rapid and persistent antifungal activity and symptom relief in patients with tinea corporis. Significant effects were observed within 7 days of therapy initiation, and increasing effectiveness was observed 4 weeks after therapy. (J Am Acad Dermatol 1997;37:231-5.)