Summary. A total of 12,150 cases of suspected dermatophytoses in different areas of Iran were studied between 1986 and 1991. The age groups most commonly infected were 1–9 and 20–29 years. Clinical diagnosis was confirmed in only 9345 cases by laboratory examination. Of these positive samples, 1633 cases were found to be positive by direct microscopic observation only, 429 by culture only and 7283 by both techniques. Scalp ringworm of children was the most common type of tinea. But according to the rate of infection, tinea corporis, tinea pedis, tinea cruris, tinea manuum, tinea unguium and tinea barbae were the next most prevalent in that order. The frequencies of dermatophytes isolated from patients were as follows: Microsporum canis 19.4%, Trichophyton rubrum 16.5%, Epidermophyton floccosum 14.9%, Trichophyton mentagrophytes var. interdigitale 14.6%, Trichophyton verrucosum 11.5%, Trichophyton mentagrophytes 6%, Trichophyton violaceum 8.7%, Trichophyton schoenleinii 5.5%, Trichophyton tonsurans 1.3%, Trichophyton erinacei 0.8% and Microsporum gallinae 0.2%.Zusammenfassung. In verschiedenen Gebieten im Iran wurden über 6 Jahre hinweg (1986–1991) insgesamt 12150 Patienten mit Verdacht auf Dermatophytose untersucht. Die am stärksten infizierten Altersgruppen waren die 1–9‐und 20–29‐Jährigen. Es wurden 9345 Patienten bei den Laboruntersuchungen als positiv beurteilt. Von diesen waren 1633 Patienten nur direktmikroskopisch, 429 nur kulturell und 7283 in beiden Techniken positiv. Tinea capitis wer die bei Kindern vorherrschende Dermatophytose. Den höchsten prozentualen Anteil bei den Infektionen hatte Tinea corporis, gefolgt von Tinea pedis, Tinea cruris, Tinea manuum, Tinea unguium und Tinea barbae. Folgende Dermatophytenarten wurden gefunden: Microsporum canis 19.4% Trichophyton rubrum 16.5%, Epidermophyton floccosum 14.9%, Trichophyton mentagrophytes var. interdigitale 14.6%, Trichophyton verrucosum 11.5%, Trichophyton mentagrophytes 6%, Trichophyton violaceum 8.7%, Trichophyton schoenleinii 5.5%, Trichophyton tonsurans 1.3%, Trichophyton erinacei 0.8% und Microsporum gallinae 0.2%.