A titanium halide containing catalyst component for polymerization of olefins which is prepared by reacting a magnesium hydrocarbyloxide with a silicon compound having at least one 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 halide of an element selected from the group consisting of elements of Groups IIIa, IVa, and Va of the Periodic Table of elements.