Hydrogel based on acrylamide and acrylic acid was synthesized and crosslinked by gamma radiation at an absorbed dose of 8 kGy. Swelling properties of the hydrogel in water and in methyl violet and Congo red solutions were investigated. The results showed that the swelling rate of the hydrogel depends on the pH and the ionic nature of the dye. Diffusion of water and dyes solutions within the hydrogel was found to be of non-Fickian character. Contrary to the swelling behavior, the capacity of the hydrogel to adsorb dyes seems to be higher at weak pHs. Concerning metal ions uptake, the results showed that adsorption of Cu2+ increases with pH increasing from pH1 to pH4.