The present technology relates to a pre-polymerized catalyst component for the polymerization of olefins, characterized by a non-stereospecific solid catalyst component comprising Ti, Mg and a halogen and an amount of a (co)polymer of an alpha-olefin CH2═CHR1, where R1 is a C1-C12 hydrocarbon group ranging from 0.1 to 500 g per g of said solid catalyst component. In some embodiments, the (co)polymer is characterized by an isotacticity, expressed in terms isotactic pentads, of higher than 60 molar % and an intrinsic viscosity, measured in tetraline at 135° C., of at least 1.0 dL/g.