Women with angiographically proven coronary heart disease (CAD) had higher postprandial concentrations of small chylomicron-remnants, measured as IDL apo B48, than women without CAD. Fasting TG concentrations were not different and within the normal range. Thus, the postprandial concentration of small chylomicron-remnants could identify women at high CAD risk within a normolipidemic population. Replacement therapy with 17beta-estradiol improved the clearance of chylomicron-remnants by 41% and attenuated the postprandial reduction in HDL-cholesterol by 66%. This improvement in postprandial lipid metabolism can explain part of the protective effect of estrogens against CAD.