Between January 1974 and December 1984, 3816 patients underwent isolated CABG at this hospital. During this 11-year interval, the number of patients having operation annually as well as the mean age at operation of the patients have increased significantly. The increase in the mean age from 51.9 years in 1974 to 59.4 years in 1984 occurred while the operative mortality rate fell significantly from 3.9% in 1974 to 2.0% in 1984. Although the overall incidence of major stroke was 1.8%, the stroke rate increased during this interval to 2.4% from 1982 to 1984. This higher stroke rate correlates significantly with the increasing age of the CABG patients, with the stroke risk five times greater for patients in their 70s compared with patients between 51 and 60 years old. Specific risk factors for the development of stroke during CABG in addition to age were examined and discussed.