It has been found that hydrogels may be formed by microwave irradiation of aqueous solutions containing appropriate combinations of polymers. This new method of hydrogel synthesis yields sterile hydrogels without the use of monomers, eliminating the need for the removal of unreacted species from the final product. Results for two particularly successful combinations, poly(vinyl alcohol) with either poly(acrylic acid) or poly(methylvinylether-alt-maleic anhydride), are presented. Irradiation using temperatures of 100-150 degrees C was found to yield hydrogels with large equilibrium swelling degrees of 500-1000 g g(-1). Material leached from both types of hydrogel shows little cytotoxicity towards HT29 cells.