To improve equilibrium water content, dehydrothermally crosslinked poly(vinyl alcohol) (PVA) hydrogel was grafted with N-vinyl pyrrolidone (NVP) or acrylic acid (AA) monomer using gamma-radiation. Swelling behavior of the grafted hydrogels was studied in phosphate-buffered saline, and cell viability was evaluated using fibroblast cells from mouse connective tissue. Equilibrium water content of AA- and NVP-grafted PVA hydrogel ranged between 40-60% and 60-80%, respectively, depending on radiation dose and monomer concentration. For maximum degree of swelling, the optimum monomer concentration and radiation dose were 20% by weight and 20 kGy, respectively. Fibroblast cells seeded on NVP-grafted hydrogel had an extended oval morphology while those seeded on AA-grafted PVA had a rounded spherical morphology. These results support the use of NVP for grafting PVA to increase swelling and improve cell viability. (C) 2004 Wiley Periodicals, Inc.