Radiation induced crosslinking of carboxymethylchitin (CMCht) and carboxymethylchitosan (CMChts) has been investigated both by electron beam (EB) and gamma-irradiations. The highest crosslinking efficiency, measured as gel content of obtained hydrogels, by EB irradiation was 72 and 50% for CMCht and CMChts, respectively, at polymer concentration of 40% at room temperature. For irradiation crosslinking at different temperatures by gamma-irradiation, the best ratio of crosslinking to degradation processes was obtained at low temperature for low concentrated polymers and at high temperature for high concentrated ones. Both hydrogels revealed significant swelling properties in deionized water, with maximum water uptake 241.2 and 63 g water/g dry gel for CMCht and CMChts, respectively. Biodegradation tests, including enzymatic controlled microorganisms degradations and soil burial, have indicated that both hydrogels undergo spontaneous biodegradation with satisfactory results. (c) 2006 Wiley Periodicals, Inc.