Thirty-seven uncemented primary porous coated anatomic (PCA) total hip arthroplasties (THA) that were performed in 33 patients for the diagnosis of avascular necrosis (AVN) between June 1984 and December 1986 were reexamined at four- to six-year follow-up periods. Final clinical evaluation showed an 86-point average Harris hip rating (range, 47-100 points), which had improved from an average preoperative rating of 42 points (range, 20-61 points). Thigh pain, which was usually not functionally limiting, occurred in 11 patients (25%), and seven patients (16%) had a moderate or severe limp. Nine patients (20%) required the use of a cane. Long-term radiographic evaluation in 37 hips demonstrated acetabular cup migration in one hip, acetabular lucencies in four hips (11%), and acetabular bead loosening in ten hips (27%). Femoral subsidence occurred in five hips (14%) and femoral bead loosening in 11 hips (30%). Thirty hips (81%) demonstrated radiographic evidence of stable bony ingrowth. No revisions were performed for aseptic loosening, but two prostheses were removed for infection. These results of uncemented THA in patients with AVN appear to be as good or better than the results reported for cemented arthroplasty in AVN at this interval of a follow-up period. This study supports the use of uncemented devices, especially with the newer designs and increasing surgical experience in this difficult patient population.