A titanium halide containing catalyst component for polymerization of olefins which is prepared by reacting a magnesium hydrocarbyloxide with a silicon compound having a hydrogen-silicon bond, contacting the reaction product with an electron donor compound, contacting the resulting contact product two or more times with a titanium halide and between one of the multiple titanium halide contacts, contacting the titanium halide contacted solid with a halogenated hydrocarbon.