Background: Tinea pedis is one of the most comrnon dermatoses in the general population. But its prevalence in the general populat,ion was not yet reported in Korea. Objective : Prevalence of tinea pedis and associated tinea unguium were checked in the general population. Methods : Six hundred fifty eight persons from 179 families of the college students were evaluated. Clinical examinatior. for tinea pedis and onychomycosis and collecting scales from the suspicious lesions of the family members were perforrned by educated college students. Then dermatologists exarnined those specimens mycologically by KOH ~tnount and fungal culture. Results . The results were as follows 1. The prevalence of tinea pedis was 41.2% in the studied 658 persons. 2. Among all 271 patients with tinea pedis, 201 strains of dermatophytes were isolated. They were 143 strains of Trichophyton(T) rubrum, 49 strains of T. mentagrophytes and 9 mixed infections of T. rubrum and T. mentagrophytes. In the co existence of i,inea pedis and tinea unguiurn, isolated species were corresponding. 3. Among 179 families, 143 families (79.9%) had at least one patient with tinea pedis. The isolated species of derrnatophytes in a farnily were one organism, 71.4% and two or more organisms, 28.6% of 77 familiys with more than one patient. Conclusion : In our study, the prevalence rate of tinea pedis was 41.2%. That suggests that tinea pedis is a wide spr .ad disease in healthy adult in Korea. (Kor J Dermatol 1997;35(1): 114-120)