The treatment of undisplaced femoral neck fracture in the elderly population is still controversial. We analysed the outcome of cancellous screw fixation for undisplaced femoral neck fracture in patients over 70 years. Materials and methods. From 1998 to 2003, ninety-seven patients with undisplaced femoral neck fracture, aged over 70 and treated with cancellous screw fixation were retrospectively identified. Full clinical data was available for 79 of the 97 patients identified. All patients had in situ fracture fixation. Results. Of the 79 patients, M:F was 22:57, average age was 81.3 years. The average inpatient stay was 13.2 days. The mean follow-up was 12 months. 24 patients had Garden type I and 55 type II fractures. 26 (32.9%) patients did not return to their pre-morbid mobility status, 5 (6.3%) did not return to their preadmission dwelling (2 went to residential homes and 3 to nursing homes). We had documented radiographic details in 46 patients: 41 patients had a healed fracture on radiographs (89.1%), 5 patients had AVN, 4 patients had non-union and 1 patient had AVN with non-union. The radiographic failure rate was 22%. 15 patients had evidence of screw back out with healed fracture. 12 of the 46 complained of pain post-operatively of which 9 (19.6%) patients had re-operation; 6 (13%) underwent revision surgery and 3 (6.5%) required screw removal. 30-day mortality was 3.7%. 1-year mortality was 23.2% of which 16 died within the first 6 months (19.5%). Conclusion. This study shows that, in our unit, cancellous screw fixation of undisplaced femoral neck fractures in patients over the age 70 had a good outcome with a 20% re-operation rate and 22% radiographic failure rate. One third of the patients did not return to their preadmission mobility level/dwelling