The aim of this study was to investigate the effect of water-soluble sulfated ${eta}$-glucan (SBG) obtained from Ganoderma lucidum mycelia on the antihyperlipidemic and serum lipid levels in high-fat diet-induced obese rats. Five-week-old male Sprague-Dawley rats were fed a high-fat diet for two weeks to induce obesity. They were ten divided into five groups-normal control diet group (NC), high-fat control diet group (HC), high-fat diet and 200 mg/kg of SBG group (HC-HSBG), high-fat diet and 20 mg/kg of SBG group (HC-LSBG), and high-fat diet and 20 mg/kg of lovastatin group (HC-Lov)-and fed one of five diets for two more weeks. Although food intake and final body weight after four weeks of SBG consumption were similar in the five experimental groups, food efficiency ratio was higher in the high-fat diet groups(2, 3, 4, and 5) than in the NC group. In evaluating the hematological parameters of the rats, the neutrophil and monocyte ratios were higher in the HC-HSBG, HC-LSBG, and HC-Lov groups than in the HC group. Serum lipid profiles were analyzed after a 12 hr fast at the end of the study. Total cholesterol, triglyceride, and low-density lipoprotein cholesterol (LDL-C) levels were significantly lower in the HC-HSBG and HC-LSBG groups than in the HC group. These results suggest that chemically engineered sulfated mushroom ${eta}$-glucan (SBG) might contribute to lower cholesterol and lipid levels in blood.