This review presents a brief account of more than 450 diverse medical research projects and programmes that have been assisted by the Office for National Statistics and its predecessors up to June 1996. It underlines the importance of many of these studies both for the practice of clinical medicine and surgery and as the basis for public health policy, and provides a public account of a research service that began as an unplanned by-product of the system developed to administer GP payments in the NHS. The publication also draws the attention of the research community to a facility with increasingly wide potential for clinical, epidemiological and public health research.