The effects of dietary supplementation with Hizikia fusiformis on anti-hyperlipidemic activities were investigated in an animal study in which normal rats were fed Hizikia fusiformis, Hizikia fusiformis ethanol extract and Hizikia fusiformis ethanol extract residue. Serum total lipid and triglyceride levels were significantly (P<0.05) reduced in rats fed Hizikia fusiformis ethanol extract residue at a dose of 200 mg/kg body weight when compared to hyperlipidemic control rats. There were also significant decreases in serum total cholesterol and LDL-cholesterol levels in the rats fed Hizikia fusiformis ethanol extract residue at 200 mg/kg body weight. In addition, the atheroscrelosis index and superoxide dismutase in blood lipids were significantly (P<0.05) lowered in rats fed Hizikia fusiformis ethanol extract residue at 200 mg/kg body weight, as compared to control rats. In conclusion, Hizikia fusiformis and Hizikia fusiformis ethanol extract residue had beneficial antihyperlipidemic and antiarteriosclerosis effects.