We have experienced some difficulties in anatomical reduction and osteosynthesis of femoral neck fracture due to its specific anatomical structuret. The purpose of this study are to analyse attribilting factors of postoperative collapse and aseptic necrosis in femoral neck fractures. We studied 62 cases of femoral neck fracture treated with the internal fixation from February 1995 to August 1997 at Gil General Hospital. Average follow up period was 1.6years. We analyzed age, sex, operation interval, Garden stage, Pauwel angle, Singh index, fracture site and the fixation method. The results obtained were as follows : Increased incidence of collapse and aseptic necrosis was noted with higher Garden stage(Garden stage 4), wider Pauwel angle(over type 2), under 40 year or over 60 year old age, woman and larger operative interval.