The clinical usefulness of 3278 mycological cultures obtained from skin lesions has been assessed. This number represents the requests for mycological identification at the University Dermatology Department in Zurich during 1972. Most specimens were obtained from skin, nails and hair, but blood, faeces, urine and pus were also submitted. Among the dermatophytes Trichophyton rubrum and Trichophyton mentagrophytes were most commonly found and Candida albicans in the yeast group. Cultures were positive more often than direct microscopic examination in all specimens. This was particularly striking with sputum and hair specimens. In view of the time-consuming techniques and the inevitably long delay in obtaining laboratory identification of pathogenic fungi in dermatology requests for identification seem to be justified only if required for diagnosis and treatment in particular of nail infections with Griseofulvin. If fungi can be demonstrated microscopically their identification by culture is rarely necessary and microscopy should always be undertaken by the clinician. In systemic mycoses laboratory identification of the infecting organism is essential.