This study was conducted to examine the effect of dietary iron levels on lipid metabolism, antioxidative and antithrombogenic capacities in 16-month-old rats. Thirty-two Sprague-Dawley male 16-month-old rats weighing 618 $pm$ 6 g were raised for 10 days with medium-iron diet (35 ppm in diet) and blocked into 4 groups according to their body weights. One of groups was sacrificed to obtain initial data and the rest 3 groups were raised for 3 months with experimental diets containing different levels of iron (5 ppm, 35 ppm, and 350 ppm). Total lipid, triglyceride and total chole-sterol concentrations in plasma and liver, HDL-cholesterol concentration in plasma, fecal total lipid triglyceride and total cholesterol excretions, thiobarbituric acid reactive substances (TBARS) level in plasma LDL + VLDL (low density lipoprotein + very low density lipoprotein) fractions, blood-clotting time and eicosanoids levels in plasma were measured. The results are as follows: Plasma total lipid, triglyceride and total cholesterol concentrations, TBARS level in plasma LDL + VLDL fractions were increased and blood-clotting time tended to be shortened during 3 months of experimental period. Low (5 ppm) iron diet improved lipid metabolism via increasing HDL-cholesterol and fecal choles-terol excretion. High (350 ppm) iron diet decreased plasma total lipid, triglyceride and total cholesterol concentrations as compared to medium (35 ppm) iron diet and lowered body weight and epididymal fat pad weight. On the other hand, TBARS level in plasma LDL + VLDL fractions and blood-clotting time were increased with high iron diet. It is plausible that low iron diet improves lipid metabolism, antioxidative and antithrombogenic capacities in 16-month-old rats.