Rationale, aims and objectives This national clinical audit aimed to develop and implement a methodology to assess the appropriateness of prescribing for patients over the age of 65 in hospitals, general practice and nursing homes. Methods Organizations providing health care in the National Health Service in these three sectors were recruited into multi-disciplinary and inter-organizational local coalition teams. Prescription data and relevant clinical data were collected electronically on a customized database. The appropriateness of prescribing for specific conditions among the patients sampled was assessed by simple computerized algorithms, and users were provided with feedback to stimulate discussion and change. Use of the software tool was demonstrated to be feasible and its data reliable. Participants were re-audited, after a period of nationally guided and locally driven intervention, to evaluate levels of change. Local efforts to stimulate change and barriers to change were collected qualitatively. Results and conclusions The investigation revealed encouraging results and demonstrated the ability of audit to improve the quality of clinical services in given circumstances, although a multiplicity of questions relating to cost and methodology remain to be addressed.