A process for preparing a thermoplastic molding material based on pulverulent polyphenylene ethers and aromatic vinyl polymers by melt extrusion at from about 200.degree. C. to about 350.degree. C., comprising compacting and sintering the pulverulent polyphenylene ether under pressure, with the optional application of heat, to form a porous compact, feeding the latter in the form of agglomerates having a particle size of from about 0.5 mm to about 20 mm into an extruder, mixing and melting the agglomerates with the aromatic vinyl polymer and optionally with additives and then extruding the molten mixture.