Objective. - To assess the relationship between coffee consumption and risk of coronary heart disease (CHD) among women. Design. - Prospective cohort study with coffee consumption measured in 1980, 1984, and 1986, and follow-up through 1990. Setting. - Female registered nurses in the United States. Participants. - A total of 85 747 US women 34 to 59 years of age in 1980 and without history of CHD, stroke, or cancer. Main Outcome Measure. - Ten-year incidence of CHD (defined as nonfatal myocardial infarction or fatal CHD). Results. - During 10 years of follow-up we documented 712 cases of CHD. After adjustment for age, smoking, and other CHD risk factors, we found no evidence for any positive association between coffee consumption and risk of subsequent CHD. For women drinking six or more cups of caffeine-containing coffee per day in 1980, the relative risk was 0.95 (95% confidence interval, 0.73 to 1.26) compared with women who did not consume this beverage. Similarly, there was no association when the first 4 years of follow-up were excluded, when nonfatal and fatal CHD end points were examined separately, or when we updated coffee consumption in 1984 or 1986 and examined only CHD during the next 2-year interval. Further, there was no association with caffeine intake from all sources combined or with decaffeinated coffee consumption. Conclusions. - These data indicate that coffee as consumed by US women is not an important cause of CHD.