Recent reports have shown that some displaced supracondylar humerus fractures can be treated in a delayed fashion the day following injury and complication rates will not be increased. This study determined if the quality of the reduction, as determined by restoration of Baumann's angle, is affected by surgical timing. Forty two patients ranging in age from 2 to 12 years were treated. Delayed intervention was defined as > 8 hours post-injury. Acute intervention occurred in 25 patients with a mean age of 5.5 years. Delayed intervention occurred in 17 patients with a mean age of 5.8 years. Baumann's angle was restored to within an average of 2.2 degrees of the contralateral elbow in the acute group and to within 1.2 degrees in the delayed group. Gartland type 2 fractures were more likely to be delayed in this retrospective study and these fractures showed better improvements in Baumann's angle restoration than did type 3 injuries when treated in a delayed fashion. In type 2 injuries and type 3 injuries without neurovascular compromise, delaying operations until the next morning will not compromise the quality of the reduction.