Congenital pseudarthrosis of the clavicle, as observed in a review of the literature, is a rare condition of uncertain etiology which usually presents on the right side. Four of 10 cases were treated by surgical repair of the pseudarthrosis with excision of the non-union and internal fixation with a Steinmann pin and cancellous bone graft. A major postoperative complication in one case consisted of an acute massive neuropraxia of the brachial plexus (recognized 6 hours postoperatively), and was successfully treated by immediate removal of the internal fixation. Ten months postoperatively, the patient was experiencing only minimal weakness of the right opponens muscle. Roentgenograms at this time showed that the pseudarthrosis had healed but with angulation of the clavicle.