Objective: To determine the association between the use of hormone replacement therapy (HRT) and coronary calcium, in postmenopausal women who had no history of coronary artery disease by double helical computed tomography (CT). Methods: We used CT to compare the prevalence and extent of coronary calcium in 41 postmenopausal women who were on HRT from the first year of menopause and 37 age-matched controls who had never used HRT. Results: Both groups had a similar rate of smoking, hypertension, a positive family history, and hypercholesterolemia. Coronary calcification was observed in 28.2% of the 78 women studied. The prevalence of coronary calcium was significantly lower among HRT users; six of the 41 (14.6%), compared with 16 of the 37 nonusers (43.2%) (P < .01). The recorded risk factors had no effect on the prevalence of coronary calcium. Stepwise logistic regression analysis, including age, coronary risk factors, and HRT use as independent variables, yielded HRT as the only variable determining the presence of coronary calcium (odds ratio = 0.2; 95% confidence interval 0.06, 0.63; P = .006). Conclusion: The lower incidence of coronary calcium in the HRT users suggests that HRT is associated with decreased prevalence of the coronary calcification.