Flexible polyolefin compositions with improved balance of properties particularly for applications where softness and ductility at low temperature is requested comprising: A) from 20 to 40% by weight of a crystalline polymer fraction consisting of a propylene homopolymer, or a copolymer of propylene, or mixtures thereof, said crystalline fraction having a xylene insoluble fraction at 25° C. 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 propylene with one or more alpha-olefins, and optionally with minor quantities of a diene; said copolymer or blend containing ethylene in a quantity lower than 40% by weight. the fraction soluble in xylene at 25° C. of said polyolefin composition having IVgpc lower than 2.5 dl/g, Mw/Mn (GPC) equal to or higher than 4, Mz/Mw (GPC) equal to or higher than 2.5 Said polyolefin composition optionally further comprising an inorganic filler (II) selected from flame-retardant inorganic fillers and inorganic oxides or salts.