Objectives. This study investigated the effects of hormonal therapy on large arterial properties. Background. Arterial stiffness is an emerging risk marker for coronary heart disease and is potentially modifiable. Postmenopausal use of hormonal therapy is associated with a lower risk of coronary heart disease. Methods. Total systemic arterial compliance (SAC) and pulse wave velocity (PWV) were determined in 26 premenopausal and 53 postmenopausal women, 26 of whom were taking hormonal therapy. Results. Arterial compliance was greater in the premenopausal group (mean ± SEM 0.57 ± 0.04 arbitrary compliance units [ACU]) than in the postmenopausal group not taking hormonal therapy (0.26 ± 0.02 ACU, p = 0.001). Postmenopausal women taking hormonal therapy had a significantly increased total SAC compared with women not taking hormonal therapy (0.43 ± 0.02 vs. 0.26 ± 0.02 ACU, p = 0.001). PWV in the aortofemoral region in the premenopausal women was 6.0 ± 0.2 vs. 8.9 ± 0.3 m/s (p < 0.001) in untreated postanenopausal women. However, postmenopausal women taking hormonal therapy had a significantly lower PWV than those not taking hormonal therapy (7.9 ± 0.2 vs. 8.9 ± 0.3 m/s, p = 0.01). Eleven postmenopausal women had their hormone replacement therapy withdrawn for 4 weeks, resulting in a significant decrease in SAC and a significant increase in aortofemoral PWV. Conclusions. The increased SAC and decreased PWV in women receiving hormonal therapy suggest that such therapy may decrease stiffness of the aorta and large arteries in postmenopausal women, with potential benefit for age-related cardiovascular disorders. The reduction of arterial compliance with age appears to be altered with hormonal therapy.