A computerized diabetic clinic management system, DIAMOND, has been developed with the collaboration of local general practitioners (GPs) to assist communication about diabetic patients across the district. DIAMOND is written in a Windows format using Microsoft Access and its dataset is in line with BDA and Diabcare recommendations. DIAMOND is user-friendly and includes displays and help messages throughout and does not require advanced computer knowledge. The main index contains two primary tables: a patient registration table with demographic data and an episode table with clinically important physical and biochemical measures. All entered data are coded to facilitate audit and an audit function, which automatically presents data, either numerically or graphically, is included in the report facility. DIAMOND also incorporates a system for patient education and training (PEATS) which may be operated by a health professional or the patient. Over 4500 patients in Newham are presently registered on DIAMOND with in excess of 15,000 episodes. Evaluation of this information is providing important clinical information both within individual GP practices and district-wide to assist future plans for health care provision.