In diabetic patients, mycotic infections may increase the risk of developing diabetic foot syndrome. However, little data are available on the prevalence of fungal foot infections in patients with diabetes. In a first study published using data obtained during a conference attended by patients with long-term diabetes mellitus type 1 (DM1), 78/95 patients (82.1%) showed probable pedal fungal infections, of which 84.6% (66/78) were mycologically confirmed by direct microscopy and/or culture. The dermatophyte Trichophyton rubrum was the most common (69.2% of isolates). Significant correlation was found between infection and the gender (men more frequently affected) and the age of the patients. Marked mycoses on the soles of the feet were often considered to be dry skin by the patients. In a second study, 174 [31 DM1, 112 DM2 and 29 healthy accompanying persons (HAP), family members without DM] participants at a regional patients' symposium on diabetes took part in an examination for fungal infections and neuropathy of the feet. In addition to the items of the first study, we gathered data on the quality of blood glucose control (HbA1c), peripheral neuropathy (neuropathy symptome and deficit score) and measurement of sudomotoric activity by Neuropad. Mean duration of disease was 23.6 (DM1) and 11.2 (DM2) years, mean HbA1c 7.56% (DM1) and 6.89% (DM2) and fungal foot infections were confirmed at 35.5% (DM1), 53.1% (DM2) and 37.9% (HAP) respectively. In DM2, the prevalence of positive fungal samples is significantly higher for participants with less controlled blood glucose (higher HbA1c) (P = 0.04). Mycotic foot infection is also correlated with age, gender and duration of diabetes disease. Of special interest is the finding of relatively high numbers of black fungi ('Dematiaceae') (n = 10), Phialophora europea (n = 3) being the most common one. The sudomotoric activity was impaired in a very high number of participants [107/171 (61.5%)], and was found positively correlated with the prevalence of fungal foot infection in DM2 but not in DM1 and HAP. The high prevalence of fungal infections detected in DM1 as well as in DM2 diabetics is remarkable, especially considering this highly motivated collective. Therefore, it appears that the feet of diabetics require more diagnostic, therapeutic and preventive care in terms of mycotic infections and sudomotoric dysfunction than previously thought.