The aim of this work is to propose a new method for determining the size distribution of submicronic particles by inversion of the measured angular scattering of light. This method relies on the determination of a function R ∗ g by angular scattering. The variation of this function informs us about the polydispersity of the aggregates size. We show that, by supposing the nature of the size distributions (lognormal), it is possible to determine the governing parameters of these distributions.