Injury to the tarsometatarsal joint (or Lisfranc's joint) is uncommon and usually caused by high energy trauma. A case of such an injury from falling off a mountain bike is reported. The radiograph was initially thought to reveal a simple metatarsal fracture but the injury was subsequently diagnosed as a divergent fracture dislocation of the tarsometatarsal joint. Considerable swelling of the foot and ankle was reduced with a regime of ice and compression with a pneumatic boot so that reduction and internal fixation could proceed as quickly as possible. On discharge, the patient was fully weightbearing with a pain free normal gait thus making an excellent recovery.