Most centres cross-match between 2 and 4 units of blood preoperatively for primary Total Hip Arthroplasties (THA), but is this necessary? We aimed to quantify the use of blood after THA in our centre, and to advocate a safe, evidence-based protocol for its use. We looked at the blood requirements of 118 consecutive THAs over a 6 month period. Records of all patients were analysed. Mean pre-operative Hb levels for both males and females were within the normal range. All patients had post-operative blood checks. Results showed that 345 units were cross-matched, but only 114 units (33%) were used. Only 28 of the 114 units (24%) were transfused on the day of surgery. 0% of patients needed intra-operative transfusion, or blood urgently. We conclude that blood should not be routinely cross-matched for primary THA. We advocate a policy of only group and saving of blood in the majority of patients that undergo primary THA, and cross-matching of blood if and when needed. However, the 1–2% of patients that have antibodies present in the blood should have blood cross-matched and available pre-operatively. If needed urgently, O-negative blood can be used or with modern cross-matching techniques, ABO compatible blood can be available from a grouped sample within 5-10 minutes. This is a method sanctioned by the British Blood Transfusion Society, and validated in the literature. Over one year this could save our trust up to £40,000 per year without compromising patient safety.