Data from the Framingham Study, a population-based prospective study of 5,209 persons, were analyzed to determine whether a parental history of death by coronary artery disease (CAD) before or after 65 years of age was an independent risk factor for CAD of early onset (age younger than 60 years) or late onset (age 60 years or older) among the men and women in the cohort. Death due to CAD in parents was associated with a 30% increase in the risk of CAD. The effect was apparently stronger for an early CAD outcome, with adjusted relative risks of 1.5 for early and 1.2 for late outcome CAD. The effect of parental CAD death on risk was not mediated by other shared risk factors for CAD. These findings were similar for those with either a mother or a father with CAD, if CAD onset in the offspring occurred before the age of 60 years. For persons with CAD at age 60 years or older, maternal CAD death was a stronger predictor of CAD than paternal CAD death. The association with parental history of CAD was similar among men and women in the cohort, with adjusted relative risks of 1.3 and 1.2, respectively. However, early age of parental CAD death may account for the association among women (RR = 1.6), whereas late age of CAD death for either parent was associated with the risk of CAD among men (RR = 1.4). © 1989.