A filled polyolefin composition comprising: a) 15 to 40% by weight of a flexible heterophasic polyolefin composition, comprising the following fractions (wherein the total of A and B fractions is 100%): A) from 20 to 40% by weight of a crystalline polymer fraction consisting of a propylene homopolymer, or a copolymer of propylene with one or more comonomers selected from ethylene and a CH 2 =CHR alpha-olefin, where R is a C 2 -C 8 alkyl radical, or mixtures thereof; said homopolymer or copolymer containing at least 85% by weight of units derived from propylene, said crystalline fraction having a fraction insoluble in xylene at 25°C (as determined according to the experimental part) of at least 90% by weight; B) from 60 to 80% by weight of an elastomeric fraction consisting of a copolymer or blend of copolymers of ethylene with one or more comonomers selected from propylene and CH 2 =CHR alpha-olefins, where R is a C 2 -C 8 alkyl radical, and optionally with minor quantities of a diene, or mixtures thereof; said copolymer or blend containing units derived from ethylene in a quantity lower than 40% by weight; the fraction soluble in xylene at 25°C of said polyolefin composition having IVgpc (as determined according to the experimental part) lower than 2.5 dl/g and a broad molecular weight distribution Mw/Mn equal to or higher than 4, Mz/Mw equal to or higher than 2.5; b) 40 to 80% by weight of an inorganic filler selected from flame-retardant inorganic fillers and inorganic oxides or salts; and c) 5 to 25 % by weight of an elastomeric polymer or polymer composition having flexural modulus (ISO 178) lower than 60 MPa, Shore A (ISO 868) lower than 90 and Tg (DMTA) lower than -20°C; wherein the sum of a), b) and c) is 100%. a) 15 to 40% by weight of a flexible heterophasic polyolefin composition, comprising the following fractions (wherein the total of A and B fractions is 100%): A) from 20 to 40% by weight of a crystalline polymer fraction consisting of a propylene homopolymer, or a copolymer of propylene with one or more comonomers selected from ethylene and a CH 2 =CHR alpha-olefin, where R is a C 2 -C 8 alkyl radical, or mixtures thereof; said homopolymer or copolymer containing at least 85% by weight of units derived from propylene, said crystalline fraction having a fraction insoluble in xylene at 25°C (as determined according to the experimental part) of at least 90% by weight; B) from 60 to 80% by weight of an elastomeric fraction consisting of a copolymer or blend of copolymers of ethylene with one or more comonomers selected from propylene and CH 2 =CHR alpha-olefins, where R is a C 2 -C 8 alkyl radical, and optionally with minor quantities of a diene, or mixtures thereof; said copolymer or blend containing units derived from ethylene in a quantity lower than 40% by weight; the fraction soluble in xylene at 25°C of said polyolefin composition having IVgpc (as determined according to the experimental part) lower than 2.5 dl/g and a broad molecular weight distribution Mw/Mn equal to or higher than 4, Mz/Mw equal to or higher than 2.5; A) from 20 to 40% by weight of a crystalline polymer fraction consisting of a propylene homopolymer, or a copolymer of propylene with one or more comonomers selected from ethylene and a CH 2 =CHR alpha-olefin, where R is a C 2 -C 8 alkyl radical, or mixtures thereof; said homopolymer or copolymer containing at least 85% by weight of units derived from propylene, said crystalline fraction having a fraction insoluble in xylene at 25°C (as determined according to the experimental part) of at least 90% by weight; B) from 60 to 80% by weight of an elastomeric fraction consisting of a copolymer or blend of copolymers of ethylene with one or more comonomers selected from propylene and CH 2 =CHR alpha-olefins, where R is a C 2 -C 8 alkyl radical, and optionally with minor quantities of a diene, or mixtures thereof; said copolymer or blend containing units derived from ethylene in a quantity lower than 40% by weight; b) 40 to 80% by weight of an inorganic filler selected from flame-retardant inorganic fillers and inorganic oxides or salts; and c) 5 to 25 % by weight of an elastomeric polymer or polymer composition having flexural modulus (ISO 178) lower than 60 MPa, Shore A (ISO 868) lower than 90 and Tg (DMTA) lower than -20°C;