Several different methods were used to evaluate the average particle diameter and the particle size distribution of different types of polymer latexes. Monomodal and bimodal latexes were tested with different instrumental methods. It was found that standard QELS methods were suitable for monomodal latexes. In the case of a bimodal latex, multiangle dynamic light scattering and separative methods offered adequate estimates of the average particle size of both populations, as well as of the relative quantities of each population in the final latex.