This study was performed to investigate the effects of liquid culture of Agaricus blazei on the lipid metabolism and enzyme activities in growing male rats. Sprague-Dawley rats were given four different types of diets for a succeeding period of 5 weeks, respectively: a normal diet group (7% corn oil), a high fat diet group (7% com oil + 15% lard), a 20 or 30% Agaricus diet groups (high fat diet + 20 or 30% Agaricus in water) according to the levels of Agaricus supplementation. The body weight gains, food intake, food efficiency ratios, and hepatic, kidney, spleen and pancreas weights of the rats fed 20 or 30% Agaricus diets were similar to those of the rats fed high fat diet. The epididymal fat pad weight of the rats fed high fat diet and 20 or 30% Agaricus diets were significantly higher than that of the rats fed normal diet. The concentrations of serum triglyceride, total cholesterol, LDL-cholesterol and HDL-cholesterol, and the activity of glutamic pyruvic transaminase in the rats fed 30% Agaricus diet were significantly lower than those in the rats 114 high fat diet. But the concentrations of hepatic total cholesterol and triglyceride of rats fed the 20 or 30% Agaricus diets were similar to those of rats fed the high fat diet. The HDL-oholesterol/total-cholesterol ratio of the rat fed 30% Agaricus diet was significantly higher than that of the rats fed high fat diet, The activity of glutamic oxaloacetic transaminase in the rats fed 20 or 30% Agaricus diets were similar to those in the rats fed high fat diet. There were no differences in the concentrations of total protein, hemoglobin and glucose, and the activities of alkaline phosphatase, and the atherogenic index in the serum among the experimental groups. These results showed that the 30% Agaricus diet feeding decreased the total cholesterol, the triglyceride and the LDL-cholesterol, and increased the HDL-oholesterol/total cholesterol ratio in serum of rats.