Adult female rats fed laboratory chow of low cholesterol content were trained by swimming for 77 days. Plasma cholesterol concentration decreased 38% compared to sedentary controls. Whole body cholesterol metabolism was studied by injection of [14C]cholesterol tracer and determination of the plasma cholesterol-specific activity during the last 49 days of the experiment. The rate constant for elemination of cholesterol from the body was 31% higher in swimming than in sedentary animals, and the size of the rapidly-exchanging cholesterol pool was 28% smaller. These results suggest that enhanced cholesterol excretion or catabolism accompanies exercise training in the rat.