The radical copolymerization reactions of (2-hydroxyethyl,methacrylate)-(2-acrylamido-2-methylpropanesulfonic acid), HEMA-AMPS, and (N,N-dimethylacrylamide)-(2-acrylamido-2-methylpropanesulfonic acid), DMAA-AMPS, are exhaustively studied by micellar electrokinetic chromatography (MEKC). Two new MEKC procedures are developed that allow us to follow the monomer consumption together with the copolymer synthesis for the two systems, i.e., HEMA-AMPS and DMAA-AMPS. The effects of the conversion and composition on the chemical composition distribution as well as on the molecular weight are analyzed by using this analytical technique.,The large possibilities of MEKC for obtaining interesting information about synthesis progress, nature, and composition of the formed ionic copolymers are demonstrated. Moreover, it is shown that capillary electrophoresis instrumentation can be used to monitor the electrical conductivity of the reaction product obtained at different copolymerization stages of the HEMA-AMPS system in order to clarify the polymerization mechanism.