From January 1988 to March 1995, we performed 66 consecutive cementless bipolar hemiarthroplasties for displaced femoral neck fractures in elderly patients with serious medical illness and evaluated the clinical and radiological results. Only 41 patients (62. l%) were followed-up for more than two years and only 15 patients (22.7%) visited the hospital regularly. The mean age of the patients was 74.3 years (range, 62 to 92 years). Twelve patients were men and 54 were women. The hospital- ization period was less than 3 weeks for 80.3% of patients (mean period, 32.7 days). Walking with partial weight-bearing was begun at the mean of 4.7 days (range, 1-2l days) postoperatively. All patients acquired initial stability of their prostheses. Daily activity of life was excellent or good in 78.0% (32 patients) of the followed-up patients. For patients who visited regularly, Harris hip scores were higher than 80 points in 80.0% (12 patients) and all prostheses had stable fixation by bone ingrowth and no loosening. Acetabular protrusion was not detected. Early or late complications were insignificant. The postoperative mortality rate was 4.5%, and the follow-up mortality rate was 12.2% in the second year, 4.9% in the third year, and 2.4% in the fourth year. Cementless bipolar hemiarthroplasty in elderly patients with displaced femoral neck fracture and high surgical risk showed satisfactory results despite poor bone quality and osteoporosis.