Aims: To compare open and closed surgery in supracondylar fractures (SCHF) of the children and evaluate the complications with delayed surgical timing. Methods: 99 children with displaced extension-type SCHF were treated surgically. Between July 1996 and May 1997 all of the SCHF were treated with open reduction through a posteromedial incision (44 patients, mean age 10.7). This goup didnñt have closed reduction attempt previously. Between May 1997 and July 1998 most of the SCHF were treated with closed reduction and percutaneous crossed pin þxation (55 patients, mean age 7.6). The patients were followed radiologically and clinically 35 months (27–46) for the open and 21 months (16–27) for the closed reduction group. They were evaluated with complications, the clinical and radiological valgus, ßexion and extension degrees compared with the contr-lateral normal elbow. The average period between the injury and the operation was 15 (11–48) hours for open and 17 (10–72) hours for closed group. Results: Valgus degree loss was 5.1û (0û Ð 20û) for open surgical group and, 3.6û (0û Ð 23û) for closed group against the contrlateral elbow. Flexion deþciency was 8.61û (0û Ð 20û) for open and 5.25û (0û Ð 15û) for closed group. Extension gap was 6.23û (0û Ð 22û) at the open group, while closed group had a loss of 0.6û (0û Ð 12û). Conclusions: Open and closed groups did not have statistically signiþcant difference for ßexion range and valgus angles. Extension gap was signiþcantly better for closed treatment group. A reasonable delay of the treatment does not increase the risk of complications.