This study compares women and men undergoing coronary artery bypass grafting. Factors before and after coronary surgery were examined to identify variables related to mortality and morbidity. The study population included 465 women and 465 men matched for age (mean age 64.2 years) who underwent first time isolated coronary artery bypass grafting between 1983 and 1988. There were higher incidences of systemic hypertension, diabetes mellitus, postmyocardial infarction angina, thyroid gland disease, arthritis (p less than 0.001 for all), acute myocardial infarction (p = 0.03), congestive heart failure (p = 0.03), and emergency surgery (p = 0.02) in women, whereas more men had peptic ulcer disease (p less than 0.001). The in-hospital death rate was not significantly different (women 4.3% vs men 3.7%). For all subjects, emergency surgery (p less than 0.001), significant left main narrowing (p less than 0.05) and renal disease (p less than 0.001) were related to death, whereas history of myocardial infarction (p less than 0.05) and diabetes (p less than 0.05) were related to death only in men. Age and body surface area were not related to death. After surgery men had a higher incidence of atrial arrhythmia (p less than 0.001), and women had a higher incidence of congestive heart failure (p less than 0.001). Although women did not have a higher mortality rate, the data suggest that women and men do not share all the same predictors of mortality after surgery.