A novel vinyl monomer, 1-(2-methacryloyloxyethyl) carbamoyl-sn-glycero-3-phosphorylcholine (MCGPC), was synthesized from sn-3-glycero-phosphorylcholine (GPC) and 2-methacryloyloxyethyl isocyanate (MOI) in the presence of di-n-butyltin dilaurate (BTL) as a catalyst, and its critical micelle concentration (CMC) was determined to be 2.7 x 10(-3) mol/l. MCGPC was copolymerized with n-butyl methacrylate (BMA) in the presence of a radical initiator in ethanol for 24 hr and 48 hr at 60 C. Bovine serum albumin (BSA) was adsorbed onto membranes prepared from copolymers of MCGPC with BMA to estimate the blood compatibility of those copolymers. The BSA adsorption was reduced with an increase of the composition of MCGPC in copolymers.