A retrospective study was carried out of the outcome of 102 patients who underwent a second operation for myocardial revascularisation, necessitated by persistence or recurrence of intractable angina after their first coronary bypass procedures. Operative mortality was 2%. During follow up of the survivors (mean interval 36.4 months) five died, two after further operation, and five underwent further surgery. Sixty eight patients reported an improvement in their symptoms, 57 of whom claimed to have little or no angina. Less favourable results were recorded for those patients reviewed with longer follow up. No useful indicators of prognosis were identified. The problem of angina in patients who have already received bypass grafts is likely to increase as more revascularisation surgery is performed. Reoperation offers a reasonable prospect of helping some of these patients, but not all will be suitable. Their long term prognosis remains uncertain.