This prospective study of 1000 femoral neck fractures (476 intertrochanteric and 524 subcapital) found the pre-injury mobility to be the most significant determinant for post-operative survival. The intrahospital mortality of the 975 surgically treated fractures was 11.3 per cent. Non-operatively treated fractures had a mortality of 60 per cent. The best predictors of morbidity and discharge mobility were age and pre-injury mobility. Delay was significant in the development of morbidity but only after 30 h from admission. Internal fixation produced a lower mortality than uncemented hemiarthroplasty. The use of acrylic cement was associated with an increased morbidity and mortality rate in hemiarthroplasties. Neither the grade nor the experience of the operating surgeon had an effect on mortality or morbidity.