Copolymerization of 2-ethylhexyl acrylate and acrylonitrile in emulsions and microemulsions containing sodium dodecyl sulfate as an emulsifier was investigated, as a function of initiator concentration, temperature, monomer-feed composition, and surfactant concentration. The emulsions were observed to turn into transparent/translucent and stable latexes, mimicking the properties of true microemulsion latexes, on polymerization. The rate of emulsion polymerization was found to be faster than that of the microemulsion polymerization. The rate of polymerization, percentage conversion, and final number of latex particles were found to be a function of initiator concentration, reaction temperature, and acrylonitrile concentration in feed. The rate of polymerization showed a dependency of -0.05 power of the surfactant concentration in the area covering emulsion and microemulsion regions. Intrinsic viscosity values showed that the products from true microemulsion polymerization were of higher molecular weight than those from "emulsion-to-microemulsion" The decrease in the particle size with conversion in emulsion polymerization was attributed to the role of the coemulsifier 2-ethylhexyl acrylate and engulfing of the initial polymerization system by the local heat production during polymerization.