In this paper a mathematical model for emulsion copolymerization of several monomers in tank reactors, proposed recently by the authors (Saldivar et al., 1996), is first validated with experimental data obtained in our laboratory. Then, a systematic methodology for model validation is presented and illustrated with application to the system methyl methacrylate/styrene. The method of numerical solution of the model is also discussed and shown to be crucial for the successful application of the model to engineering and fundamental problems. Finally, the generality of the model is demonstrated by applying it to three illustrative problems : (i) simulation of complex dynamics in a flowsheet, (ii) simulation and comparison to experimental data for a semicontinuous system with a complex kinetic scheme, and (iii) start-up optimization in a flowsheet.