We undertook a randomised, controlled trial to compare the analgesic efficacy and opioid sparing effect of nerve stimulator-guided femoral nerve block with fascia iliaca compartment block in patients awaiting surgery for fractured neck of femur. Ten-centimetre visual analogue pain scores were measured before and 2 h after the block and opioid consumption was recorded in the 12-h period after the block. One hundred and ten patients were randomly assigned. Femoral nerve block provided superior pre-operative analgesia for fractured neck of femur compared with fascia iliaca compartment block. The difference in the mean reduction of pain score after the block was 0.9 (95% CI 0–1.8); p = 0.047. Patients receiving a femoral nerve block required less morphine after the block than those receiving fascia iliaca compartment block (p = 0.041).