The treatment of supracondylar fracture of humerus in children has so many pitfalls as to be once called "supracondylar dilemma". The authors analyzed the follow-up results of fifty-six displaced extension type supracondylar fractures treated by percutaneous pinning and by open reduction from 1982 to 1989. The mean age was 7.6 years, ranging from three years to fifteen years. Forty three fractures were treated by percutaneous pinning and thirteen by open reduction. According to the modified Flynn's criteria, the results of the treatment by percutaneous pinning were excellent 36%, good 32%, fair 25% and poor 7%, while those of open reduction were 8%, 42%, 8% and 42% , respectively, on average follow up of 1.4 years. Post-operative complications were found in seven cases (16.7%) of percutaneous pinning, and in five cases(38.5%) of open reduction. Poorly chosen surgical approach for open reduction was appeared to be related with unsatisfactory results. We believe that percutaneous pinning was a simple, effective method for treatment of displaced supracondylar fractures of the humerus. We agree, however, that open reduction is still indicated if manipulative reduction before pinning is unacceptable, or if the fracture is complicated by neurovascular or open injury.