Previous published works described suspension polymerization processes for the production of spherical core-shell poly(vinyl acetate)/poly(vinyl alcohol) (PVAc/PVA) particles with regular morphology for use as embolic agents in vascular embolization procedures. Although the clinical performance of the produced particles was regarded as excellent, the produced PVAc/PVA particles were prone to agglomeration during storage. For this reason, methyl methacrylate is now used as comonomer in order to increase the glass transition temperature of the final product and prevent agglomeration of polymer particles. The final expansion of particles, intended to control the density of the polymer beads, also exerts a beneficial effect on the rate of particle agglomeration. Therefore, a methodology to obtain spherical poly(vinyl acetate)-co-poly(methyl methacrylate)/poly(vinyl alcohol) (PVAc-co-PMMA/PVA) particles with core-shell structure is presented in this work.