The authors studied 31 patients with Tinea cruris, corporis or pedis interdigital. The patients were treated with 100 mg of itraconazole, once a day, during the lunch, for 15 days. Mycological and clinical evaluations were performed at the pre-treatment, by the end of treatment and 2 weeks after finishing the treatment. The results showed that itraconazole is effective for the treatment of dermatophytosis, at the studied posology. with 100% of mycological cure. Clinical evaluation showed a significant reduction (Friedman test - p < 0.001) of signs and symptoms. No side-effect was registered.