OBJECTIVE We evaluated total hip arthroplasty and short-term results in the treatment of coxarthrosis due to neglected congenital dislocation or severe dysplasia of the hip. METHODS Cemented total hip arthroplasty was performed in 23 hips of 22 patients (2 men, 20 women; mean age 48.6 years; range 28 to 65 years) with osteoarthrosis due to congenital dislocation or severe dysplasia of the hip. The acetabular component was placed at the level of the true acetabulum; four patients required augmentation with autogenous bone grafts due to severe acetabular deficiency. Femoral shortening osteotomy using a subtrochanteric step-cut osteotomy was performed in seven patients with high-riding hips. Five patients underwent proximal femoral shortening after the trochanter major was osteotomized and distally advanced. All patients were evaluated with the use of the Merle d'Aubigne and Postel hip scores. Radiologic evaluations were made by preoperative and follow-up radiographs. The mean follow-up was 52.8 months (range 30 to 108 months). RESULTS According to the Merle d'Aubigne and Postel hip scores, the results were excellent in 17 hips (74%), good in four hips (18%), fair in one hip (4%), and poor in one hip (4%). One hip required revision because of nonunion of the acetabular graft. The femoral stem was fractured in one patient. Complications included temporary sciatic nerve palsy in one patient, deep venous thrombosis in one patient, early dislocation in one patient, and nonunion of the femur in one patient who underwent subtrochanteric step-cut osteotomy. CONCLUSIONS Total hip arthroplasty for congenitally dislocated or severely dysplastic hips is more effective than other treatment methods. Long-term results can be improved by the use of contemporary cementing techniques.