OBJECTIVE--To investigate differences between hospitals in clinical management of patients admitted with fractured hip and to relate these to mortality at 90 days. DESIGN--A prospective audit of process and outcome of care based on interviews with patients, abstraction from records with standard proforma, and follow up at three months. Data were analysed with chi 2 test and forward stepwise regression modelling of mortality. SETTING--All eight hospitals in East Anglia with trauma orthopaedic departments. PATIENTS--580 consecutive patients admitted for fracture of neck of femur. MAIN OUTCOME MEASURE--Mortality at 90 days. RESULTS--Patients admitted to each hospital were similar with respect to age, sex, pre-existing illnesses, and activities of daily living before fracture. In all, 560 (97%) were treated surgically, by a range of grades of surgeon. Two hundred and sixty one patients (45%; range between hospitals 10-91%) received pharmaceutical thromboembolic prophylaxis, 502 (93%; 81-99%) perioperative antibiotic prophylaxis. The incidence of fatal pulmonary emboli differed between patients who received and those who did not receive prophylaxis against deep vein thrombosis (P = 0.001). Mortality at 90 days was 18%, differing significantly between hospitals (5-24%). One hospital had significantly better survival than the others (odds ratio 0.14; 95% confidence interval 0.04-0.48; P = 0.0016). CONCLUSIONS--No single factor or aspect of practice accounted for this protective effect. Lower mortality may be associated with the cumulative effects of several aspects of the organisation of treatment and the management of fracture of the hip, including thromboembolic pharmaceutical prophylaxis, antibiotic prophylaxis, and early mobilisation.