Toughened thermoplastics are prepared by mixing a water-moist elastomer component A containing up to 60% by weight of residual water with a thermoplastic polymer B and further polymers C and additives D in an extruder with mechanical dewatering of the elastomer component A, by a process in which the components A, B, C and D are fed to a twin-screw extruder which has corotating screws and essentially comprises, in the transport direction, at least one metering section in which the elastomer component A is fed to the extruder by a metering means, at least one squeeze section which serves for dewatering the component A and contains at least one retarding element and in each case at least one associated dewatering orifice, at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder, at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements, at least one devolatilization section which is provided with at least one devolatilization orifice and in which the residual water is removed as steam, and a discharge zone, the water emerging from the dewatering orifices being present partially or completely in the liquid phase, and the components C or D or mixtures thereof, together or separately from one another, being fed to one or more of the stated extruder sections, either together with the component A or B or mixtures thereof or separately from A and B.