Superporous hydrogels (SPHs) of poly(acrylamide-co-acrylic acid) [P(AM-co-AA)]/chitosan and P (AM-co-AA)/glycol chitosan interpenetrating polymer networks (IPNs) were prepared, and their swelling and mechanical properties were investigated. The introduction time of the blowing agent was determined from gelation reaction exotherms. For both SPH systems, equilibrium swelling ratios decreased in distilled water, but increased in simulated gastric fluid, as the chitosan concentration increased. Replacement of glycol chitosan for chitosan led to a significant increase in the swelling rate because of its high water affinity. Equilibrium swelling ratios were mostly governed by the ionic concentration difference between the gel and bulk phases, but the swelling rate depended upon the pore size and structure. The compressive strength of P(AM-co-AA)/chitosan IPN SPHs swollen in water was very weak, but that in simulated gastric fluid was over 60 KPa.