Determination of individual sub-micron particle size and refractive index was performed with a parametric solution of the inverse light-scattering problem. The parametric solution is based on approximating equations that relate the particle characteristics to the parameters of the indicatrix tan angular dependence of light-scattering intensity). The approximation equations allow real-time calculation of particle size and refractive index ranging from 0.5 to 1.5 mum and from 1.37 to 1.69, respectively. The applicability of the parametric solution was demonstrated with the analysis of polystyrene particles, the indicatrices of which were measured using scanning flow cytometry. We measured samples of monodisperse polystyrene particles with diameters of 0.6 and 0.83 mum. The measured indicatrices were processed with the parametric solution and best-fit regression to the Mie theory. The determined particle parameters were in a good agreement with the specifications.