A total of 90 cases of suspected dermatophytoses was observed over a period of 9 months in the city of Cusco (Peru) and in its environs. The age groups most commonly infected were 1-10 and 11-20 year old. The most common tineae diagnosed were tinea capitis (13.3%) and tinea unguium (11.1%). Only four species of dermatophytes were isolated: Microsporum canis (52.4%), Trichophyton mentagrophytes (35.7%), Tr. rubrum (9.5%) and Epidermophyton floccosum (2.4%). Dry weather, low temperature and high altitude do not seem to affect proliferation and infections by dermatophytes.