The polymers containing 2-acrylamido-2-methy1-1-propanesulfonic acid (AMPA) were prepared by radical polymerizations. The polymers were identified by FT-IR, H-1-, and C-13-NMR spectroscopies. The contents of AMPA unit in poly(AMPA-co-MAH), terpoly(AMPA-MAH-FUR), and poly(AMPA-co-EETFU) were 67, 73 and 49 mol %, respectively. The number average molecular weights of the polymers determined by GPC were in range from 5,600 to 9,200. The IC50 values of the synthesized polymers against cancer cell lines were in the range of 0.02 to 127. The in vivo antitumor activities of polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5-FU.