Results of coronary artery bypass graft (CABG) surgery in patients under age 36 who were operated upon between 1970 and 1980 at two large medical centers were compared to matched control patients, age 45 to 59 years, and 60 years and over. Patient follow-up ranged from one to 13 years (average five years). Event-free survival was significantly worse in the young group (37 percent) vs the middle aged group (61 percent, p less than 0.01) and vs the elderly group (59 percent, p less than 0.02). Failure of the operation was due to failure to improve or worsening of Canadian Cardiovascular Society anginal class, need for reoperation, subsequent myocardial infarction, or death due to cardiac causes. Risk of failure of CABG surgery in young patients was increased with the presence of cardiac risk factors. Because of the high rate of long-term failure of CABG surgery in young patients, its use in this group needs to be reevaluated relative to current aggressive medical therapy for angina.