Process for producing a catalyst system, which comprises the following steps: A) provision of a mixture of at least two different organic transition metal compounds, at least one hydrolyzed organoaluminum compound and a solvent and impregnation of a dry porous support component with the mixture from step A), with the total volume of the mixture being from 0.6 to 1.5 times the total pore volume of the support component, and also catalyst systems obtainable in this way and their use for olefin polymerization.