Mountain biking grew from a trend to a serious branch of sport. This article presents the different subspecialties within the sport, the injury rates and the types of injuries among high-class and recreational bikers. The experiences made during several years as a team physician of top athletes as well as the statistics from the Swiss accident insurance company SUVA are the basis for the data presented. The issue of mountain bike-related concussions is particularly discussed since this type of injury is a point of increasing concern in the recent sports traumatology literature.