The authors assessed the relation between the extent and progression of baldness and coronary heart disease. Baldness was assessed twice, in 1956 and in 1962, in a cohort of 2,017 men from Framingham, Massachusetts. Extent of baldness was classified in terms of number of bald areas: no areas bald (n = 153), one area bald (n = 420), two areas bald (n = 587), and all areas bald (n = 857). Men who were assessed both times and who had two or fewer bald areas during the first evaluation were classified into one of three groups: "mild or no progression," "moderate progression," or "rapid progression." The cohort was followed for up to 30 years for new occurrences of coronary heart disease, coronary heart disease death, cardiovascular disease, and death due to any cause. The relations between the extent and progression of baldness and the aforementioned outcomes were assessed using a Cox proportional hazards model, adjusting for age and other known cardiovascular disease risk factors. Extent of baldness was not associated with any of the outcomes. However, the amount of progression of baldness was associated with coronary heart disease occurrence (relative risk (RR) = 2.4, 95% confidence interval (CI) 1.3-4.4), coronary heart disease mortality (RR = 3.8, 95% CI 1.9-7.7), and all-cause mortality (RR = 2.4, 95% CI 1.5-3.8). Rapid hair loss may be a marker for coronary heart disease.