A new process that combines the excellent morphology control of Ti-based catalysts with the unique features of polyolefins from metallocenes has been devised. First, propylene is polymerized with the Ti-based catalysts, having spherical form; then, activated metallocene catalysts are introduced into the porous PP spheres, through an in situ impregnation and drying process, once the Ti has been deactivated. Then, the olefins polymerization, catalyzed by the metallocene, is carried out in gas phase. This step, as well as the morphology of the as-polymerized polymer particles, has been investigated in detail. New heterophasic copolymers (PP/EPR) having free-flowing spherical form have been achieved, and the morphology of the copolymer spheres pointed out that the rubber is well dispersed inside the polymer granule.