The aim of the present work was to assess the blood compatibility of monomethoxy (polyethylene glycol)-poly (D,L-lactic-co-glycolic acid)-monomethoxy (polyethylene glycol) (MeO-PEG-PLGA-PEG-OMe, PELGE) triblock copolymer as a propriety material for intravenous use in vitro. Three different proportional triblock copolymers were synthesized. According to the International Standard Organization (ISO) and US Pharmacopoeia, XXIII recommendations, siliconized glass tube was used as the negative control sample, while nonsiliconized glass tube was used as the positive control. The blood compatibility of the films of Poly (D,L-lactic and glycolic acid) (PLGA) was evaluated by dynamic clotting time, activated partial thromboplastin time (APTT), and plasma recalcification time (PRT) measurements, platelet adhesion investigation, and hemolytic ratio analysis. The results revealed that blood compatibility of the materials was good. Nanoparticles made by this kind of materials might be promising for intravenous use. (c) 2006 Wiley Periodicals, Inc.