The authors describe the injury of the lower extremity caused by putting the child's leg between the spokes of bicycle wheel during ride. The result is contusion of soft tissues of the leg and ankle or the fracture of the shin in a typical place. The injury requires a through treatment of soft tissues and sometimes also reduction of the fracture under total anaesthesia with subsequent fixation by plaster of Paris. On the basis of the group of 52 patients it has been proved that the mentioned injuries but for exceptional cases heal without sequelea. The authors emphasize the importance of the prevention of this injury by the installation of a plastic cover over the bicycle frame.