In a follow up study of 110 consecutive patients in adult which fractures of femoral neck treated by multiple pining, compression hip screw, endoprosthesis, total hip replacement arthroplasty could be followed for a minimum of lyear or until a definite result had been reached from 1981 to 1989 January. 1. The incidence of unsatifactory result was 19.1% after multiple pining, 27.4% after compression hip screw, 18.1% after endoprosthesis, and 16.7% after total hip replacement arthroplasty. 2. Thirteen unsatisfactory results following multiple pinning were due to aseptic necrosis which was definite in eleven cases, and late nonunion in two. Three poor results followed compression hip screw and were due to aseptic necrosis in two and late nonunion in one. Six unsatifactory results followed endoprosthesis were due to loosening in one and painful hip in five. Three poor result followed by total hip replacement arthroplasty were due to dislocation in one and bed sore in one, and deep wound infection in one. 3. Aseptic necrosis was more influenced by the original displacement at initial injury. 4. From this study it was concluded that in displaced femoral neck fractures of adult, prosthetic replacement gives a more reliable result.