Polypropylenes having a reduced tendency to white fracture, which contain A) from 70 to 95% by weight of a highly isotactic polypropylene having anisotactic index of more than 90 and a melt flow index between 0.1 and 100 g/10 min, it being possible for the polypropylene to be a homopolymer of propylene or a copolymer of propylene with one or more .alpha.-olefins, having a propylene content of at least 50 mol %, and B) from 5 to 30% by weight of a highly amorphous polypropylene having a crystalline polypropylene fraction of up to 10% by weight with an enthalpy of fusion of not more than 40 J/g and a melt flow index between 0.1 and 100 g/10 min, it being possible for the polypropylene to be a homopolymer of propylene or a copolymer of propylene with one or more .alpha.-olefins, having a propylene content of at least 80 mol %.