The pitted keratolysis (Keratolysis sulcata) is an infectional disease affecting the horny layer of the soles of the feet, less common of the palm. Initially circular lesions can be found, which can coalesce to large defects, possibly combined with local malodor and hyperhidrosis. The pitted keratolysis is caused among others by Corynebacteria, Dermatophilus congolensis and Micrococcus sedentarius. It is found more frequently in regions with tropical climate. Occlusion and pressure play an important role as causative agents. There are rare examinations concerning the prevalence of the pitted keratolysis in non-tropical countries. Informations about the frequency of the disease among athletes highly straining their feet are lacking too. In this study the soles and palms of 184 competitive athletes in Germany were examined to determine the prevalence of pitted keratolysis compared to a control group of 165 dermatological patients with normal physical activity. The inspection of the skin areas was followed by a skin biopsy in case of suspicion and a histological examination. The existence of coccoid or filamentous elements within the skin defects then led to the diagnosis of pitted keratolysis. As a result the prevalence of pitted keratolysis among competitive athletes showed a distinct increase (13,6% vs. 0,6% within the control group). Additionally differences between sports disciplines occurred. Athletes performing jumps and sprints within their sports showed extremly high prevalences (up to 30%). Two histological types could be detected aswell. Wether these two types involved two bacterial species or corresponded with two histological appearances of one bacterial species is unclear.