To determine age-related changes in left ventricular (LV) structure and function, the authors used freehand three-dimensional echocardiography, a previously validated tomographic technique, to measure LV mass, volumes, and derived parameters in 94 sedentary, but ambulatory and clinically healthy, adult male and female volunteers aged 20-94. LV volumes and mass were significantly greater in men than in women (p<0.001) and remained greater after adjustment for body surface area and height (p<0.05). Declines in end-diastolic and stroke volumes with age were reduced or absent after accounting for body size. By multivariate analysis, age accounted for only about 6%-11% of the variance among LV volumes and mass, in comparison with body surface area and gender, which accounted jointly for about 46%-77% of the variance. In conclusion, changes occur in LV structure and function with normal aging, but these changes are relatively minor when body size and gender are taken into account.