Fifty-two consecutive primary total hip arthroplasties were performed in forty-seven unselected patients by one surgeon. The prosthesis included a hemispherical porous-coated acetabular component, inserted without cement and with the use of screws through three peripheral flanges, and a femoral component, inserted with a so-called second-generation cementing technique. No patient was lost to radiographic follow-up, and the clinical result was known for all patients. The average age at the time of the index operation was fifty-seven years (range, twenty-nine to seventy-nine years). Four patients (four hips) who died were last examined less than ten years postoperatively (the minimum follow-up period for this study) and one hip was revised, leaving forty-seven non-revised hips in forty-two surviving patients who were followed for at least ten years. The duration of clinical follow-up of these forty-two patients averaged 12.3 years (range, 10.8 to 13.3 years), and the duration of radiographic follow-up averaged 12.1 years (range, 10.0 to 13.0 years). One (2 per cent) of the original fifty-two hips was revised for late recurrent dislocation, without loosening, 9.7 years after the index arthroplasty. The rate of dislocation was relatively high (13 per cent; seven hips), and we believed it to be related to the shallow-chamfer acetabular design combined with the small femoral head. At the time of the latest follow-up, no femoral component was loose. One (2 per cent) of the fifty-two acetabular components was loose according to radiographic criteria, but the hip functioned well (Harris hip score, 94 points) 12.4 years after the index arthroplasty. Pelvic osteolysis developed in one hip (2 per cent); femoral osteolysis, in eight (15 per cent); and distal femoral osteolysis, in three (6 per cent). The average Harris hip score for the forty-seven non-revised hips increased from 48 points (range, 26 to 63 points) preoperatively to 89 points (range, 67 to 100 points) at the time of the most recent follow-up. Forty (85 per cent) of the forty-seven hips had a good or excellent result, whereas five (11 per cent) had a fair result (score, 74 to 79 points) and two (4 per cent) had a poor result (score, 67 and 69 points). The hybrid primary total hip arthroplasty resulted in very good clinical function at ten to thirteen years, although the rate of dislocation was high.