A study of eighty-two open reductions of congenital dislocation of the hip, with a follow-up examination of seventy-two of the hips, is presented, with details of the preoperative examination and treatment, the operative findings and procedure, postoperative care, and the results several years after operation. It is definitely shown that a fairly large percentage of congenital dislocations of the hip cannot be reduced, or the reduction maintained, by closed operation because of anatomical abnormalities about the acetabulum. It is further demonstrated that roentgenograms taken with the patient standing and under traction, as well as the ordinary recumbent views, are essential for a thorough study of these hips both before and after operation. It is particularly important that the pathological condition and mechanism at the hip be carefully studied at operation. It is our practice now to study the hip at operation upon exposure of the capsule, after opening the capsule, and after removing the ligamentum teres, to determine the factors interfering with reducton and stability, and we test the stability of the hip after reduction with upward pressure on the leg during gradual adduction and in various positions of rotation. The rotation procedure is valuable in determining the necessity for correction of anteversion. Furthermore, there is so much individual variation in these hips that they cannot be grouped together indiscriminately and compared superficially in attempts to present the best apparent results. It is felt that a more definite method of comparison is required for properly evaluating the results of the operation than the usual "excellent", "good", or "fair" ("poor" rarely appears in the literature) and, for want of an accepted standard, our cases are reported in some detail and a method of evaluating motion given.