Background: Dermatophytes are a group of closely related fungi that invade keratinized tissues (skin, hair and nails) of humans and animals and produce infections called dermatophytosis. Our objective was to determine causative agents of dermatophytosis in Gorgan, North of Iran. Methods: Data was based on collecting specimens from 1108 patients clinically suspected to have fungal infection during five years from 2003 through 2007. Specimens were collected from hair, nail and skin and were investigated by direct examination and cultured in Sabouraud dextrose agar. Fungal colonies were identified by macroscopic and microscopic examination and supplementary tests. Results: 351 samples out of 1108 were positive for dermatophytes and 277 ones had positive cultures. Epidemophyton floccosum was the most frequent species (70.4%) followed by Trichophyton rubrum (14.5%) and Microsporum audouinii (7.2%). Regarding the location of the lesions, groin and nails were the most frequent sites that developed dermatophytosis in the majority of the patients. Conclusion: Dermatophytosis is probably still one of the most infectious diseases in Iran. The anthropophilic (E.fluoccosum) and zoophilic (T. rubrum) species were the most common causes of dermatophyte of tinea in Gorgan, north of Iran. The frequency of tinea was higher in females and tinea cruris showed a remarkably increasing rate and can be an important public health issue in Gorgan.