An extensive psychosocial questionnaire was administered to 1674 coronary free individuals participating in the Framingham Heart Study between 1965 and 1967. The respondents were followed for the development of coronary heart disease (CHD) over an eight-year period. Women (aged 45-64 years) who developed CHD scored significantly higher on the Framingham Type A behavior, suppressed hostility (not showing or discussing anger), tension, and anxiety symptoms scales than women remaining free of CHD. Type A women developed twice as much CHD and three times as much angina as Type B women. In a multivariate analysis, Framingham Type A behavior and not discussing anger were independent predictors of CHD incidence when controlled for the standard coronary risk factors and other psychosocial scales. Men exhibiting Framingham Type A behavior, work overload, suppressed hostility (not showing anger), and frequent job promotions were at increased risk of developing CHD (especially in the age group 55-64 years). Among men aged 45-64 years, Type A behavior was associated with a twofold risk of angina, myocardial infarction, and CHD in general, as compared to Type B behavior. The association was found only among white-collar workers and was also independent of the standard coronary risk factors and other psychosocial scales. This prospective study suggests that Type A behavior and suppressed hostility may be involved in the pathogenesis of CHD in both men and women.