A new algorithm is presented for the prediction of equilibrium morphology in latex particles. Thermodynamic equilibrium calculations of the interfacial free energies associated with a large array of possible morphologies serve to create a continuous free-energy surface upon which the preferred morphology is located. When the computations are performed on a 486DX33 PC, the calculations are essentially instantaneous. The graphical output can be refreshed on the monitor screen in less than 2 s. The algorithm is applied to simulate the conversion-dependent morphology for several latex systems composed of polystyrene and poly(methyl methacrylate) and two very different surfactants.