Thirty-five dermatologists enrolled 256 patients to assess the safety and efficacy of ketoconazole 2 percent cream, applied once daily, in the treatment of tinea pedis, tinea cruris, and tinea corporis. Of these, 232 were eligible for efficacy evaluation based on mycologic evidence. Symptoms were assessed after four and eight weeks of treatment; relapse was assessed four weeks after the end of treatment. Total symptom scores decreased significantly during the treatment period. A marked or excellent response to treatment was observed in 82 percent of the cases. At the end of treatment 113 patients had all of their symptoms scored as absent or mild. Of these, three patients relapsed (2.7 percent) and had at least one symptom scored as moderate or severe at the follow-up visit. Only 7.2 percent (six of eighty-three) of the patients with negative findings on potassium hydroxide examination at the end of treatment showed positive findings at the follow-up visit. Three patients reported local irritant reactions to ketoconazole, two of whom discontinued treatment.