Acrylamide (AAm)/acrylic acid (AAc) hydrogels in the cylindirical form were prepared by gamma-irradiating binary systems of AAm/AAc with 2.6-20.0 kGy gamma-rays. The effect of the dose and relative amounts of AAc and pH on the swelling properties, diffusion behavior of water, diffusion coefficients, and network properties of hydrogel systems was investigated. The swelling capacities of AAm/AAc hydrogels were in the range of 1000-3000%, while poly(acrylamide) (PAAm) hydrogels swelled in the range of 450-700%. Water diffusion into hydrogels was found to be non-Fickian-type diffusion. Diffusion coefficients of AAm/AAc hydrogels were found between 0.79 x 10(-5) and 2.78 x 10(-5) cm(2) min(-1).