Supracondylar fracture of the humerus is one of the common fractures in children. This fracture is not infrequently associated with neurovascular complications. Although management of neurovascular injuries associated with the fracture itself is well described in the literature, little information is available concerning nerve injuries associated with pinning itself. During the period of 2 years and 2 months from May, 1989 to June, 1992, 88 children with supracondylar fractures of the humerus were treated at Dong San Medical Center, Keimyung university. Of these, seven cases of postoperative nerve palsy associated with reduction and pinning were experienced. The results are summerized as follows; 1. Eighty-eight cases of supracondylar fractures were classified according to Wilkins method. The majority of them were type III fractures (74 case). the remainders were type I (6 case) and type II (8 case) fractures. 2. Of the eighty-eight cases, ten fractures were treated by closed reduction and casting; fifty fractures, by closed reduction and percutaneous pinning; and twenty-eight fractures, by open reduction and pinning. 3. Of seventy-eight fractures treated with pinning, seven cases (9%) of nerve palsy (six ulnar nerve palsy and one median nerve palsy) developed after operation. 4. Five nerve palsies resolved spontaneously within 8 months. One patient was lost during follow up and another patient showed full recovery of motor power but mild hypoesthesia in ulnar nerve territory 17 months after operation. 5. When the postoperative nerve palsy is certainly not the result from direct pin-related injury, early nerve exploration or neurolysis may rarely to indicated.