Chitosan hydrogels may be formed by various mechanisms. In this study, we aimed to form hybrid polymer networks of chitosan with alginate using a crosslinker which enabled the covalent binding of the two macromolecules. The structural and thermal characterization of these hydrogels was performed by using Fourier transform infrared (FTIR) and differential scanning calorimeter (DSC). The morphological analysis of the crosslinked material was investigated by scanning electron microscopy (SEM) and a scanning probe microscope with atomic force microscope (AFM) attachment. The swelling properties of these gels were analyzed in water and in phosphate buffered saline (PBS) solution. The presence of alginate in a chitosan/alginate hydrogel was shown to support the hydrogel stability. Compared to chitosan/alginate (1/2) hydrogel prepared with 1 wt% DCC, the swelling of chitosan/alginate (1/2) hydrogels prepared with 3 wt% DCC was limited. To measure the degree of cell proliferation, the hydrogels were seeded with L929 mouse fibroblasts and cell numbers measured by neutral red uptake assay. The cell attachment was also followed by (SEM) photography. It was observed that chitosan/alginate (1/2) hydrogels with 1 wt% (DCC) provides a better environment for cell attachment and proliferation. This study presents functional hydrogel formation by crosslinked chitosan and alginate, a novel biomaterial which also supports cell growth. (C) 2013 Published by Elsevier B.V.