Abstract: A process for the continuous production of organopolysiloxane compositions which vulcanize at elevated temperature and have a viscosity of at least 500 Pa·s at 25° C., involves mixing and homogenizing high-viscosity organopolysiloxanes and crosslinking additives in a kneading cascade having at least two kneading chambers arranged in series proximate one another, containing two axially parallel kneading tools which can be driven in the same or opposite directions, and which are connected to one another by means of openings transverse to the axes of the kneading tools, with the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, and the temperature in the kneading chambers containing crosslinking additives being not more than 95° C.