Method for preparing a spray-dried composition for use as a polymerization catalyst

This invention relates to catalyst compositions, methods of making such compositions, and methods for making polymers therefrom. A method of making a spray-dried composition using a solution or mixture comprising the reaction product of a magnesium halide, a solvent, an electron donor compound, and a transition metal compound and an inert filler comprising substantially spherical particles having an average particle size ranging from 1 m to about 12 m.