A mathematical model for emulsion copolymerization process of 1,3-butadiene and methyl methacrylate is presented and validated with experimental data in a batch reactor. The model is able to explain the effects of changes in temperature, monomer-to-water ratio, emulsifier concentration, initiator concentration, and monomer feed composition on the time evolution of monomer conversion, average particle size, and pressure. Despite its simplicity and a reduced number of adjustable parameters, the model is capable of accounting for the basic features of emulsion copolymerization processes and can be used in engineering applications.