In 1992 the British Thoracic Society arranged a series of voluntary interdepartmental peer reviews. Their prime objective was to help to improve services by enabling clinicians to share experiences and ideas on the organisational aspects of the service and training provided. This paper outlines the planning and implementation of the scheme and some of the key results, and discusses the benefits and difficulties of such 'peer reviews'. Much of the benefit comes from the free exchange of ideas at the time of the reviews and 82% of the participants felt that they had picked up new ideas during the review. In their reports, reviewers outlined the strengths and weaknesses of the units and put forward a list of their key recommendations for change. Importantly, in half of the reviews the reviewers identified factors requiring change that had not been anticipated by the reviewed units. In most cases, the reports were subsequently shown to the managers concerned. One year after the review, 53% of 144 major recommendations had been achieved or were imminent. This form of voluntary peer review benefits both the reviewers and the reviewed and could well be adopted by other specialties.