A process for preparing an aqueous dispersion of particles composed of addition polymer and finely divided inorganic solid (composite particles), in which process ethylenically unsaturated monomers are dispersely distributed in aqueous medium and polymerized by the method of free-radical aqueous emulsion polymerization by means of at least one free-radical polymerization initiator in the presence of at least one dispersely distributed, finely divided inorganic solid and at least one dispersant, which comprises using a monomer mixture comprising >0 and ≦10% by weight of at least one ethylenically unsaturated monomer containing an epoxide group.