A total of 168 patients with tinea pedis, but without onychomycosis, were treated with 1 cycle of terbinafine (TBF) (1 cycle: defined as 250 mg/day for 1 week). KOH preparation for direct microscopy was performed 4, 8 and 12 weeks after starting therapy to determine if testing was positive for tinea. Patients with no negative results on KOH examination or no evidence of obvious clinical improvement at 8 weeks, another cycle of the therapy was prescribed. The "cure", "no cure", "dropout", and "discontinuation/unevaluable" rates were 89.3%, 4.8%, 4.8% and 1.2%, respectively. The number of cycles required for cure in the plantar type was 1 cycle in 65.9% and 2 cycles in 54.5% of cases; in the interdigital type, 1 cycle in 79.1% and 2 cycles in 20.9% of cases; and mixed type, 1 cycle in 29.1% and 2 cycles in 60.9% cases. Among patients who were followed for at least 3 years after cure, the relapse rates were about 10% each year: 1 year, 11.3%; 2 years, 8.9%; and 3 years, 11.2%. The relapse rate of about 10% each year over a 3-year period suggests that reinfection may be likely.