1. The effects of edible oyster mushroom Pleurotus ostreatus on plasma and liver lipid profiles and on the plasma total anti-oxidant status were estimated in hyper- and normocholesterolaemic Long Evans rats. 2. The feeding of 5% powder of the fruiting bodies of P. ostreatus mushrooms to hypercholesterolaemic rats reduced their plasma total cholesterol by approximately 28%, low-density lipoprotein-cholesterol by approximately 55%, triglyceride by approximately 34%, non-esterified fatty acid by approximately 30% and total liver cholesterol levels by > 34%, with a concurrent increase in plasma high-density lipoprotein-cholesterol concentration of > 21%. However, these effects were not observed in mushroom-fed normocholesterolaemic rats. 3. Mushroom feeding significantly increased plasma fatty acid unsaturation in both normo- and hypercholesterolaemic rats. 4. Plasma total anti-oxidant status, as estimated by the oxidation of 2,2'-azino-bis-[3-ethylbenz-thiazoline-6-sulphonic-acid], was significantly decreased in mushroom-fed hypercholesterolaemic rats, concomitant with a decrease in plasma total cholesterol. 5. The present study suggests that 5% P. ostreatus supplementation provides health benefits, at least partially, by acting on the atherogenic lipid profile in the hypercholesterolaemic condition.