Poly (acrylamide-dimethyld iallylammonium chloride) (PAM-DMDAAC) particles have been prepared via dispersion polymerizations using poly (vinyl pyrrolidone) (PVP) as a steric stabilizer in ethanol-water media. The monomer reactivity ratios of acrylamide (AM, r(1)) and dimethyldiallylammonium chloride (DMDAAC, r(2)) were determined as 6.664 and 0.120, respectively, which means that PAM-DMDAAC is a nonideal copolymer. The effects of various polymerization parameters (e.g., concentration of monomer and initiator, medium polarity, the ratio of AM to DMDAAC, initial temperature and ethylene diamine tetraacetic acid disodium (EDTA)) on the intrinsic viscosity and conversion of copolymer have been investigated. The copolymer was characterized by FTIR and NMR. The optimum operating conditions for preparing PAM-DMDAAC were determined as ethanol content 50%, C(monomer) (wt %) 40%, n(Am): n(DMDAAC) 8 : 2, C(initiator) (Wt %) 0.04% and initiate temperature 40 degrees C. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 1496-1502, 2011