In this study, we investigated the effects of lowering the fat and cholesterol in the diets of 26 Korean hypercholesteolemic men($geq$240mg/dl). They consumed 2378kcal/day with 20.9% of the energy deriving from fat, and a cholesterol intake of 282mg(118mg/1000kcal). The experimental diet consisted of 2400kcal, the same as their usual diet, but the fat content was restricted to 15%, and the cholesterol level to below 100mg/1000kcal. The subjects kept to this diet for four weeks and were asked to maintain their usual life activities during the experimental period. The dietary intake and levels of plasma lipid, lipoprotein-cholesterol and apoprotein of the subjects were analyzed before, two weeks into, and after four weeks dietary intervention. After two of the dietary intervention, there were no significant changes of plasma total cholesterol or triglyceride levels but there was some changes of phospholipid level. However, after four weeks, the levels of plasma total cholesterol, triglyceride, and phospholipid had decreased significantly: 18.2%, 32.9%, and 11.9%, respectively. And the LDL-cholesterol and VLDL-cholesterol levels also showed a marked reduction of 18.1%, and 33.0% respectively without change of HDL-cholesterol level. There were no changes in the levels of Apo-A 1, Apo-B, or Lp(a). The changes of the plasma lipid levels were significantly associated with the changes in dietary fat intake but not the cholesterol intake. In conclusion, although the responses to the dietary intervention varied among the individual subjects, the lowering of dietary fat component from 21% to 15% of energy intake seems to be an effective way to reduce plasma cholesterol and triglyceride levels without decreasing HDL-cholesterol level. It was also found that the restriction of dietary cholesterol to below 100mg/1000kcal not seem to be effective for the hypercholesterolemic patient who already consuming below 300mg/day of cholesterol.