A polyethylene composition comprising: A) from 75% to 97% by weight of a copolymer of ethylene with one or more comonomers selected from C 3 -C 10 alpha-olefins, said copolymer having the following features: 1) a density of 0.925 g/cm 3 or higher, measured according to ISO 1183-1:2012 at 23°C; 2) a MI 2 value of 0.5 g/10 min. or greater, where MI 2 is the Melt Index measured according to ISO 1133-2:2011 at 190°C with a load of 2.16 kg; B) from 3% to 25% by weight of a polyolefin composition comprising: B I) from 5% to 35% by weight of one or more propylene homopolymer(s) or one or more copolymer(s) of propylene with ethylene and/or C 4 -C 8 α-olefin(s), containing 90% or more of propylene units, or combinations of said homopolymers and copolymers; component B I) containing 10.0% by weight or less of a fraction soluble in xylene at 25°C (XS I), both the amount of propylene units and of the fraction XS I being referred to the weight of B I); B II) from 20% to 50% by weight of a copolymer of ethylene and a one or more comonomers selected from C 3 -C 10 alpha-olefins, containing from 1.0% to 20.0% by weight of alpha-olefin units and containing 25.0% by weight or less of a fraction soluble in xylene at 25°C (XS II), both the amount of alpha-olefin units and of the fraction XS II being referred to the weight of B II); and B III) from 30% to 60% by weight of a copolymer of ethylene and propylene containing from 25.0% to 75.0 % by weight of ethylene derived units and containing from 40.0% to 95.0%by weight of a fraction soluble in xylene at 25°C (XS III), both the amount of ethylene units and of the fraction XS III being referred to the weight of B III); the said amounts of A) and B) being referred to the total weight of A) + B) and the said amounts of B I), B II) and B III) being referred to the total weight of B I) + B II) + B III). A) from 75% to 97% by weight of a copolymer of ethylene with one or more comonomers selected from C 3 -C 10 alpha-olefins, said copolymer having the following features: 1) a density of 0.925 g/cm 3 or higher, measured according to ISO 1183-1:2012 at 23°C; 2) a MI 2 value of 0.5 g/10 min. or greater, where MI 2 is the Melt Index measured according to ISO 1133-2:2011 at 190°C with a load of 2.16 kg; 1) a density of 0.925 g/cm 3 or higher, measured according to ISO 1183-1:2012 at 23°C; 2) a MI 2 value of 0.5 g/10 min. or greater, where MI 2 is the Melt Index measured according to ISO 1133-2:2011 at 190°C with a load of 2.16 kg; B) from 3% to 25% by weight of a polyolefin composition comprising: B I) from 5% to 35% by weight of one or more propylene homopolymer(s) or one or more copolymer(s) of propylene with ethylene and/or C 4 -C 8 α-olefin(s), containing 90% or more of propylene units, or combinations of said homopolymers and copolymers; component B I) containing 10.0% by weight or less of a fraction soluble in xylene at 25°C (XS I), both the amount of propylene units and of the fraction XS I being referred to the weight of B I); B II) from 20% to 50% by weight of a copolymer of ethylene and a one or more comonomers selected from C 3 -C 10 alpha-olefins, containing from 1.0% to 20.0% by weight of alpha-olefin units and containing 25.0% by weight or less of a fraction soluble in xylene at 25°C (XS II), both the amount of alpha-olefin units and of the fraction XS II being referred to the weight of B II); and B III) from 30% to 60% by weight of a copolymer of ethylene and propylene containing from 25.0% to 75.0 % by weight of ethylene derived units and containing from 40.0% to 95.0%by weight of a fraction soluble in xylene at 25°C (XS III), both the amount of ethylene units and of the fraction XS III being referred to the weight of B III); the said amounts of A) and B) being referred to the total weight of A) + B) and the said amounts of B I), B II) and B III) being referred to the total weight of B I) + B II) + B III). B I) from 5% to 35% by weight of one or more propylene homopolymer(s) or one or more copolymer(s) of propylene with ethylene and/or C 4 -C 8 α-olefin(s), containing 90% or more of propylene units, or combinations of said homopolymers and copolymers; component B I) containing 10.0% by weight or less of a fraction soluble in xylene at 25°C (XS I), both the amount of propylene units and of the fraction XS I being referred to the weight of B I); B II) from 20% to 50% by weight of a copolymer of ethylene and a one or more comonomers selected from C 3 -C 10 alpha-olefins, containing from 1.0% to 20.0% by weight of alpha-olefin units and containing 25.0% by weight or less of a fraction soluble in xylene at 25°C (XS II), both the amount of alpha-olefin units and of the fraction XS II being referred to the weight of B II); and B III) from 30% to 60% by weight of a copolymer of ethylene and propylene containing from 25.0% to 75.0 % by weight of ethylene derived units and containing from 40.0% to 95.0%by weight of a fraction soluble in xylene at 25°C (XS III), both the amount of ethylene units and of the fraction XS III being referred to the weight of B III);