Patients with hip fractures should have surgery within 36 hours of admission to hospital. This reduces mortality and is required for hospitals to receive the NHS Best Practice Tariff. Many patients with hip fractures take Warfarin and reversing the effect of this frequently delays surgery. We report the results of a case-control study. The primary outcome measure was the number of patients with an INR of 1.7 or less on the day following admission to hospital. This is considered an acceptable INR for hip fracture surgery in our department. In the control group the dose of Vitamin K given was decided by the admitting doctor based on the patients' INR. In the intervention group all patients received 5mg of IV Vitamin K on admission. They had their INR rechecked at 6:00am the following morning and a further 2.5mg of Vitamin K was given if it was 1.8 to 2.0 and a further 5mg of Vitamin K was given if it was greater than 2.0. 350 patients with hip fractures were admitted to our department and 26 (7.4%) of these were taking Warfarin. The control group contained fourteen patients who had a mean INR of 3.3 on admission. The time taken to achieve an INR of 1.7 or less was one day for four patients; two days for nine patients and three days for one patient. The intervention group contained twelve patients who had a mean INR of 2.7 on admission. The time taken to achieve an INR of 1.7 or less was one day for eleven patients and two days for one patient. There were no complications caused by Warfarin reversal. A high proportion of patients with hip fractures take Warfarin. This can be reversed promptly and safely using our protocol.