This letter presents the results of an experimental investigation of the self‐beat intensity correlation spectra of light scattered from mixtures of two sizes of polystyrene latex spheres of an approximately 1 : 2 diameter ratio. The precision of the data permits the deduction of scattering amplitude ratios (concentration ratios) and particle diameters by straightforward least‐squares analysis, which, in general, are within 5% of actual values. The use of computer‐evaluated uncertainties in calculating weighted means is found to improve the statistical analysis.