Abstract: A method of preparing curable solid polyester resin pellets and powders comprising(a) preparing a liquid mixture consisting essentially of an unsaturated polyester resin, at least one monomeric unsaturated polymerizable material containing a terminal ethylene group, and an alkaline earth metal oxide or hydroxide in an amount effective to provide a desired increase in viscosity,(b) allowing the liquid mixture to stand until the alkaline earth metal oxide or hydroxide and the polyester co-react, and a desired increase in viscosity has been attained,(c) dispersing in the mixture obtained in (b), a polymerization initiator and a filler, fibrous reinforcing material, pigment or mold release agent, or mixtures thereof,(d) extruding the mixture obtained in (c) to form dry, free-flowing pellets or powdersis described. The pellets and powders prepared in this manner are specifically suitable for molding techniques such as injection, compression or transfer molding operations.