Posterior dislocation of the carpometacarpal joints is a very rare injury. Due to the normal relative immobility of these joints and the fact that the tendons are not firmly bound in this region, unreduced dislocations do not produce serious disabilities. Better results, cosmetically and functionally, may be obtained by reduction, which is easily accomplished in an early case under local or general anaesthesia. Reduction of old cases should receive serious consideration before attempts are made, since the only improvement would be in the appearance of the hand, and it might be made a much less usable member.