Novel of temperature and pH sensitive hydrogels composed of polyampholyte (casein) and poly(N-isopropylacrylamide) were successfully synthesized via free radical polymerization. The swelling behavior of the obtained hydrogel was investigated and it was found that the synthesized hydrogel has a sensitivity to temperature, pH, and the crosslinker content. The drug release of this hydrogel was determined with salicylic acid employed as the model drug. It found that the release of salicylic acid from the hydrogel particles was affected by temperature, pH, and the crosslinker content in the copolymer hydrogels. Therefore, the novel pH and temperature sensitive hydrogel seem to be of great promise in pH and temperature sensitive oral drug release systems.