In 29 women and 53 men with asymptomatic aortic stenosis, two-dimensional (2-D) and Doppler echocardiography were performed at rest and immediately after treadmill exercise testing to examine gender difference in left ventricular geometry, systolic and diastolic function, functional status, and exercise capacity. Aortic stenosis severity was similar between men and women. Women reported more functional impairment than men (88% ± 14% vs 95% ± 7%; p = 0.02). When indexed to body surface area, women had a smaller end-diastolic volume (39 ± 14 vs 50 ± 15 ml/m²; p = 0.002), end-systolic volume (13 ± 6 ml/m² vs 18 ± 9 ml/m²; p = 0.01) and left ventricular mass (73 ± 26 gm/m² vs 84 ± 21 gm/m²; p = 0.05), but a higher relative wall thickness in systole (1.5 ± 0.4 cm vs 1.3 ± 0.4 cm; p = 0.05), and fractional shortening (43% ± 7% vs 39% ± 10%; p = 0.03). Women had higher early and late transmitral velocities than did men (early, 92 ± 24 cm/sec vs 79 ± 29 cm/sec; p = 0.05; late, 97 ± 30 cm/sec vs 68 ± 23 cm/sec; p < 0.0001), a higher time-velocity integral in early diastole (18.2 ± 4.8 cm vs 15.1 ± 4.3 cm; p = 0.006), a significantly shorter exercise duration (4.5 ± 4.1 minutes vs 8.0 ± 3.9 minutes; p < 0.0001), a greater degree of functional aerobic impairment (25% ± 48% vs 2% ± 33%; p = 0.02), and a smaller increase in cardiac output with exercise (5.4 ± 3.5 L/min vs 8.0 ± 4.3 L/min; p = 0.01), in spite of similar peak heart rate and blood pressure responses. In these asymptomatic subjects with aortic stenosis, women had smaller, relatively hypercontractile ventricles, a different diastolic filling profile, more exercise limitation, and poorer functional capacity. These findings demonstrate the importance of gender in the response of the left ventricle to chronic pressure overload.