The radical polymerization of N-acryloyl-N＇-(p-tolylsulfonyl) urea (2), prepared easily by the reaction of p-toluenesulfonyl isocyanate with acrylamide, was carried out in DMF, DMSO, or NMP at 60 degrees C by use of AIBN as an initiator to give a polymer 3 in a good yield. Copolymerization parameters of 2 were evaluated by the copolymerization with MMA. Polymer 3 was readily hydrolyzed in an aqueous NaOH solution (1M) at room temperature to give poly( acrylic acid). The reason for the higher activity for hydrolysis of 3 compared to an ordinary amide is discussed.