A composition having a Melt Flow Rate, measured according to ISO 1133 with a load of 2.16 kg at 230 °C, of from 2 to 100 g/10 min, the composition comprising: A) from 30 to 60 by weight of a polyolefin composition comprising, (all percent amounts being by weight): a) 10-50 % of a copolymer of propylene with one or more comonomer(s) selected from ethylene and CH 2 =CHR alpha-olefins where R is a 2-8 carbon alkyl, which copolymer contains from 1 to 8% of comonomer(s), in particular from 1 to 4.5% when the sole comonomer is ethylene; b) 50-90 % of a copolymer of ethylene and (i) propylene or (ii) other CH 2 =CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical, or (iii) a combination thereof, optionally with minor amounts of a diene, containing from 50 to 80% of ethylene; wherein the weight ratio b/XS of the content b of copolymer component (b) to the fraction XS soluble in xylene at room temperature (about 25 °C), both (b and XS) referred to the total weight of (a) + (b), is of 1.5 or less, and the intrinsic viscosity [η] of the said XS fraction is of 3 dl/g or more; and the total quantity of copolymerized ethylene is preferably from 30% to 65% by weight; B) from 5 to 30 wt% of a glass fiber filler; C) from 0 to 5 % by weight of a compatibilizer; D) from 10 to 40 by weight of a polypropylene component selected from propylene homopolymers, propylene copolymers containing up to 5% by moles of ethylene and/or C 4 -C 10 α-olefin(s) and combinations of such homopolymers and copolymers, wherein the Melt Flow Rate, measured according to ISO 1133 with a load of 2.16 kg at 230 °C of the polypropylene component D) is generally from 0.3 to 2500 g/10 min. A) from 30 to 60 by weight of a polyolefin composition comprising, (all percent amounts being by weight): a) 10-50 % of a copolymer of propylene with one or more comonomer(s) selected from ethylene and CH 2 =CHR alpha-olefins where R is a 2-8 carbon alkyl, which copolymer contains from 1 to 8% of comonomer(s), in particular from 1 to 4.5% when the sole comonomer is ethylene; b) 50-90 % of a copolymer of ethylene and (i) propylene or (ii) other CH 2 =CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical, or (iii) a combination thereof, optionally with minor amounts of a diene, containing from 50 to 80% of ethylene; wherein the weight ratio b/XS of the content b of copolymer component (b) to the fraction XS soluble in xylene at room temperature (about 25 °C), both (b and XS) referred to the total weight of (a) + (b), is of 1.5 or less, and the intrinsic viscosity [η] of the said XS fraction is of 3 dl/g or more; and the total quantity of copolymerized ethylene is preferably from 30% to 65% by weight; a) 10-50 % of a copolymer of propylene with one or more comonomer(s) selected from ethylene and CH 2 =CHR alpha-olefins where R is a 2-8 carbon alkyl, which copolymer contains from 1 to 8% of comonomer(s), in particular from 1 to 4.5% when the sole comonomer is ethylene; b) 50-90 % of a copolymer of ethylene and (i) propylene or (ii) other CH 2 =CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical, or (iii) a combination thereof, optionally with minor amounts of a diene, containing from 50 to 80% of ethylene; B) from 5 to 30 wt% of a glass fiber filler; C) from 0 to 5 % by weight of a compatibilizer; D) from 10 to 40 by weight of a polypropylene component selected from propylene homopolymers, propylene copolymers containing up to 5% by moles of ethylene and/or C 4 -C 10 α-olefin(s) and combinations of such homopolymers and copolymers, wherein the Melt Flow Rate, measured according to ISO 1133 with a load of 2.16 kg at 230 °C of the polypropylene component D) is generally from 0.3 to 2500 g/10 min.