Synthesis of acrylamide (AA) hydrogel from an aqueous solution has been performed with radiation processing technology using a Co‐60 gamma source. The influence of time, concentration, dose, and dose rate on swelling and water absorption properties of the hydrogel treated in different conditions such as oven‐dry (OD), room‐dry (RD), and nondry (ND) has been investigated. Swelling and hydration increase rapidly with time for first 48 hr, then become nearly constant in the range 48–336 hr. The samples prepared at lower concentrations and doses exhibit higher values of hydration and swelling but they represent a fall of these values at lower dose rate. These occur mainly as a result of the increase of crosslinking density in the hydrogel by gamma ray irradiation. Furthermore, OD samples have higher swelling and hydration values as compared with RD and ND samples. All these effects of physical parameters and the drying conditions on hydration and swelling of hydrogel are discussed.