Orientation and shape of the acetabulum was determined by the use of three-dimensional reconstruction of CT data sets in 22 patients with a total of 30 2 slipped capital femoral epiphyses. We developed an interactive three-dimensional software program to measure the anteversion and inclination of the acetabulum without projectional and pelvis tilting errors. Furthermore, we determined the height, width, depth, volume, and surface of the acetabulum as parameters describing the acetabular shape. Comparison of the affected side to the contralateral unaffected hip showed no significant differences for acetabular orientation and shape. The relationship between the degree of the slip and the acetabular orientation was calculated. No correlation was found. Based on the results of this study we conclude that the slipping of the femoral capital epiphysis has no influence on acetabular development.