Heparin-attached polyhydroxyethylmethacrylate (PHEMA) microbeads were investigated for specific removal of cholesterol from human and rabbit plasma. PHEMA microbeads were prepared by a suspension polymerization technique and activated by cyanogen bromide (CNBr) in an alkaline medium (pH 11.5). Heparin was then immobilized by covalent binding onto these microbeads. Cholesterol adsorption onto PHEMA microbeads containing two different amounts of immobilized heparin, i.e., 57.3 and 122.7 mg/g, from both hypercholesterolaemic human and rabbit plasma was investigated. The non-specific cholesterol adsorptions on the plain PHEMA microbeads were 0.47 mg/g and 0.30 mg/g from human and rabbit plasmas, respectively. About 35% and 32% of the cholesterol was removed from human and rabbit plasmas, respectively, when the heparin-immobilized PHEMA microbeads were used.