Steroid hormones are involved in the regulation of sympathoadrenal activity. Since the effect of sex steroids on the cardiovascular system and catecholamine secretion could also be exerted through an acute, nongenomic mechanism, we have studied the response to mental stress (color word test, CWT) in a group of 15 menopausal women during estrogen (100 µg of estradiol by patch), progesterone (100 mg i.m.) or placebo administration. Systolic blood pressure (SBP) increased during CWT in the three sessions (F = 11.0, p < 0.001) but the area under the curve of SBP was higher during placebo (2,855 ± 131 mm Hg·min) than during estradiol (2,585 ± 139 mm Hg·min) and progesterone (2,553 ± 179 mm Hg·min, p < 0.05 for both). Plasma epinephrine increased during CWT in the three sessions (F = 31.1, p < 0.001) and the plasma epinephrine response to mental stress was higher during placebo than during estradiol administration (F = 4.3, p < 0.01). The area under the curve of epinephrine was 10,342 ± 1,348 pmol/min·l during placebo and 7,280 ± 818 pmol/min·l during estradiol (p < 0.03). The plasma glycerol levels at the end of CWT were higher during placebo (0.26 ± 0.04 nmol/l) than during estradiol (0.19 ± 0.03 mmol/l) and progesterone (0.17 ± 0.04 mmol/l) administration (p < 0.05 for both). No significant differences were found in the responses of diastolic blood pressure, heart rate, norepinephrine and cortisol to mental stress during placebo and estradiol or progesterone administration. This study demonstrates that acute steroid administration is able to modify the cardiovascular and catecholamine response to mental stress in menopausal women.