In the VA Cooperative Study of Coronary Artery Bypass Surgery, follow-up by the participating investigators was completed in 1984 and annual centralized follow-up by the coordinating center for an additional 5 years was initiated in 1985. Follow-up was restricted to key outcomes that could be reliably obtained in most patients-survival, severity of angina, myocardial infarction and bypass surgery. Ninety-five percent of patients consented to annual follow-up by telephone or mail. At the first annual follow-up, 95% of all survivors were contacted; 95% were also contacted at the second follow-up. In the initial follow-up, survival status was known in all patients and severity of angina was recorded in 93% of survivors; all bypass operations and all but one infarct identified were documented by a discharge summary. Our results indicate that coordinating center follow-up was effective in a long-term study of a chronic disease and depended on the willingness of patients to participate, the experience of the interviewers, and the ability of the coordinating center to contact patients and retrieve outcome data. This report describes the methods used for the centralized follow-up of the surviving patients and summarizes the initial follow-up results. The limitations and advantages of this approach are also discussed.