The applicability of static light scattering as a tool for particle sizing is evaluated for spherical core-shell systems. A series of intensity-angle measurements have been made on hematite (alpha-Fe2O3) particles covered by yttrium basic carbonate (Y(OH)CO3) shells; size parameters-including polydispersity-have been deduced by means of the Aden-Kerker scattering theory, and the results have been compared to electron microscopy. Some explanations are given concerning the higher degree of polydispersity yielded by Aden-Kerker theory compared to electron microscopy observations.