This study investigated the incidence and frequency of injuries in mountainbike sports among competitive and recreational athletes. In a retrospective study design mountain-bike athletes were interviewed by means of a standardized questionnaire with regard to sports injuries and damages within the previous two years. The evaluation of time relative injury-rate was carried out under consideration of class and competition discipline. 75 % of the distributed questionnaires returned completed by 106 World-Cup (39 female symbol 67 male symbol, 23.1 y) and 134 recreational athletes (17 female symbol 117 male symbol, 27.4 y). Approximately 80 % of the World-Cup and about 50 % of the recreational athletes reported about at least one severe injury. World-Cup downhill athletes (1.08 injuries/ 1000 h) show a more than doubled time-related injury-rate in comparison with Cross-Country athletes (0.39 injuries/ 1000 h). Injuries of the lower (47 vs. 35 %) and upper extremity (40 vs. 41 %) show comparable prevalence for competitive and recreational cyclists. In the group of recreational athletes open wounds dominate, competitive athletes demonstrate a significant higher fracture-rate (p < 0.01). Within the World-Cup athletes head injuries stand out (n = 40). Although World-Cup participation does not result in essential injury-increase, the downhill discipline is characterized by a higher injury risk. Presumably in view of the performance orientation, there is a higher degree of risk readiness. Despite the riding performance and the obligatory safety equipment a remarkable number of bone and head injuries results.