A retrospective audit of blood transfusions was carried out in Cardiff Royal Infirmary (CRT) to investigate how efficiently blood was requested and used by the various clinical directorates. Excessive crossmatch/transfusion (C/T) ratios were found for a number of operations. In an attempt to improve practices, a pilot study was carried out between the Department of Haematology and the largest single requesting group, the Orthopaedic Directorate. As a result of a preliminary retrospective audit, crossmatch guidelines were revised, with more reliance on the group and antibody screen (G&S) for low-risk operations. A subsequent prospective audit showed major reductions in crossmatch requests and a general decrease in C/T ratios to very efficient levels without any patient morbidity. Blood was freed for urgent use elsewhere, and significant cost improvements resulted. This study, using the orthopaedic surgery department as a model, shows the value of inter-departmental audit and supports the experience of other centres using similar methods to make considerable savings in the amount of blood crossmatched unnecessarily.