A population-based survey, using data from the Framingham study, assessed sex-specific patterns of coronary heart disease occurring over a 26-year period of time. Among subjects ages 35 to 84 years, men have about twice the total incidence of morbidity and mortality of women. The sex gap in morbidity tends to diminish during the later years of the age range, mainly because of a surge in growth of female morbidity after age 45 years, while by that age, the growth in the male rate begins to taper off. An approximate 10-year difference between the sexes persists in mortality rates throughout the life span. The relative health advantage that is possessed by women, however, is buffered by a case fatality rate from coronary attacks that exceeds the male rate (32% vs 27%). Coronary disease manifestations differ between the sexes. Myocardial infarction is more likely to be unrecognized in women than in men (34% vs 27%). Angina pectoris in women more frequently is uncomplicated (80%), whereas in men angina tends to evolve out of infarction (66%). Also, sudden death comprises a greater proportion of male deaths than female deaths (50% vs 39%). Because women maintain a lesser probability of the disease than do men at any level of the major cardiovascular risk factors, distinctions in their risk factor profiles do not explain completely the observed disease patterns.