To evaluate the efficiency of carboxymethylchitosan (CM-chitosan)-based hydrogels as barriers for reducing postsurgical adhesions, CM-chitosan was synthesized to simplify the hydrogel-making process, and the CM-chitosan solutions were cross-linked by using gamma-ray irradiation to create the desired hydrogels instead of using chemical cross-linking reagents. The prepared CM-chitosan hydrogels were characterized by a FTIR spectroscopy, swelling behavior, gel-fraction content,and mechanical property such as gel strength of a hydrogel and the results showed a good swelling behavior and mechanical properties. Also, the radiation-induced CM-chitosan hydrogels significantly reduced and inhibited the postsurgical adhesions in the rat models. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 3682-3687, 2010