The invention relates to a process for preparing foamed polymer-modified bitumen compositions and to the use thereof for the production of asphalt. The invention also relates to foamed polymer-modified bitumen compositions obtainable by this process. Furthermore, the invention relates to a process for producing an asphalt composition and to the use thereof in road applications. The process for the preparation of the foamed polymer-modified bitumen composition comprises the following steps: i) Heating and pressurizing a bitumen to obtain a hot flowing bitumen stream, ii) Injecting under pressure an aqueous polymer dispersion into the hot flowing bitumen stream obtained in step i), to obtain a pressurized flowing mixed stream of the bitumen and the aqueous polymer dispersion; iii) Expanding the flowing mixed stream, in particular to atmospheric pressure, such that the water contained in the aqueous polymer dispersion vaporizes and foams the mixed stream to obtain a foamed polymer-modified bitumen.