Ten cases of neurotmesis of posterior interosseous nerve of the forearm were treated with mierosurgical technique from Aug, 1988 to Oct. 1990, of which, 4 cases by autogenous nerve graft and 6 cases by direct neurosuture. Eight cases have been followed-up from 4 months to 1 year after operation concerning with satisfactory results. Some questions the diagnosis, the points for attention in operation, and the relation of the results and the time when the operation done were discussed. The comparison of the results and the recovery time between the autogenous-nerve graft and direct neurosuture was made.