The present study was designed to determine the lowest dose of orally administered itraconazole and the shortest duration of therapy necessary for treatment of tinea corporis and tinea cruris. For all patients, the itraconazole dose was 100 mg twice a day immediately after meals. Twenty-eight patients received itraconazole on days 1 and 8, 12 patients received itraconazole on days 1 and 2, and five patients received itraconazole only on day 1. Clinical and mycological evaluations were performed at baseline and on day 14. Based on the clinical and mycological responses, treatment efficacy was classified as excellent, good, fair, or poor. "Excellent" and "good" responses made up 86% of the first group, 100% of the second group, and 20% of the third group. A comparison of efficacy ratings of the three regimens showed that the patients who received a single 200-mg dose had a significantly inferior outcome compared with the other two groups. We conclude that an abbreviated oral regimen of itraconazole for treatment of tinea corporis and tinea cruris requires a total dose of at least 400 mg to induce a favorable outcome.