The loci of polymerization in usual emulsion polymerizations are the polymer particles whose diameters are in the submicrometer range; therefore, each polymer particle can be considered a segregated microreactor that contains a small number of macroradicals. It is straightforward to extend the microreactor method proposed in Part 1 of this series(1) to emulsion polymerizations by taking account of the transfer processes of oligomeric radicals between phases, and as a consequence, the formation process of each polymer molecule is simulated directly. The molecular weight distribution can be significantly different from those predicted using a single constant bimolecular termination rate coefficient. The average termination rate coefficient is smaller for larger polymer particles or for longer time intervals between radical entry. Monte Carlo simulations promise to provide greater insight into the complex molecular processes that occur during emulsion polymerizations.