We investigated the hypothesis that medial femoral torsion is a predisposing factor to osteoarthritis of the hip. Anteversion was measured by biplane radiography in 44 hips (32 patients) with idiopathic osteoarthritis of the hip and a control group of 98 normal hips (49 adults). The mean and range of anteversion measures were similar in both groups. The mean was 22 degrees for osteoarthritic hips (range 3 degrees-49 degrees) and 19 degrees for normal controls (range -2 degrees-49 degrees). This difference was not significant. This study disagrees with others that propose an association between increased anterversion and osteoarthritis of the hip. Prophylactic operative correction of femoral torsion for osteoarthritis is not recommended.