The efficacy of itraconazole, a new oral triazole, was evaluated at doses of 50-400 mg/day in 64 courses: 39 with coccidioidomycosis, and 25 with other mycoses. Among patients with coccidioidomycosis, 21 had pulmonary disease; 10, bone and joint; 8, lymphatic; 6, skin and soft tissue; 3, meningeal; and 1, urogenital. After a mean of 7.1 months of treatment, 17 of 27 evaluable courses (63%) have shown a full response; 8 (30%), a partial response; and 2 (7%), no response. Response to treatment was higher in patients with a shorter duration of illness and in patients with no previous treatment. After a mean of 12 months of treatment, two of five responders off therapy have relapsed. In patients with other mycoses, diagnoses include aspergillosis in six patients; histoplasmosis and tinea in three each; alternariosis, candidiasis, cryptococcosis, blastomycosis, and chromomycosis in two each; and pseudallescheriosis in one. After a mean of 9.4 months of treatment, 14 of 23 evaluable patients (61%) have shown a full response; 2 (8%), a partial response; and 7 (30%), no response. All patients with histoplasmosis and blastomycosis have responded to therapy. There are no relapses among five evaluable responders after a mean of 9.2 months off therapy. In 512 patient months of therapy, toxicity has been minimal. Mean serum levels in patients receiving 200 mg twice daily range from 3.9 to 5.9 micrograms/ml for 8 hr after dosing, with a peak at 7 hr and wide interpatient variability. Itraconazole is well tolerated and has continued to demonstrate efficacy in the treatment of a variety of systemic and superficial mycoses.