A series of thermosensitive copolymeric hydrogels were prepared from various molar ratios of N-isopropylacrylamide (NIPAAm) and poly(ethylene glycol) methylether acrylate (PEGMEA(n)), which was synthesized from acryloyl chloride and poly(ethylene glycol) mono methylether with three oxyethylene chain lengths. Investigation of the effect of the chain length of oxyethylene in PEGMEA(n), and the amount of the PEGMEA(n), in the NIPAAm/PEGMEA(n) copolymeric gels, on swelling behavior in deionized water was the main purpose of this study. Results showed that the swelling ratio for the present copolymeric gels increased with increasing chain length of oxyethylene in PEGMEA(n) and also increased with increase in the amount of PEGMEA(n), in the copolymeric gels. However, the gel strength and effective crosslinking density of these gels decreased with increase in swelling ratio. Some kinetic parameters were also evaluated in this study. Finally, the drug release and drug delivery behavior for these gets were also assessed. (C) 2003 Wiley Periodicals, Inc.