To determine whether there is a higher frequency of mycotic infections due to dermatophytes in diabetics, 171 diabetic outpatients and 276 controls were recruited in the period 1997-98. Patients with suspicious lesions underwent mycological examination which was positive in seven diabetics and 17 controls. In diabetics the most frequent infection was tinea pedis, followed by distal subungual onychomycosis; the most frequently isolated fungus was Trichophyton mentagrophytes. The results of the study did not show a prevalence of dermatophyte infections in diabetics. No correlation was found between dermatophytosis and duration or type of diabetes and its complications, blood sugar levels or levels of glycosylated haemoglobin. None of the diabetic patients with dermatophytosis had complications related to diabetes and basal blood sugar and glycosylated haemoglobin levels indicated good metabolic control.