Ethylene polymer composition having a fusion enthalpy ΔHfus, measured by Differential Scanning Calorimetry with a heating rate of 20° C. per minute, of 60 J/g or more, comprising, all percent amounts being by weight: A) 25-55% of an ethylene polymer containing 10% or less, referred to the weight of A), of a fraction XSA soluble in xylene at 25° C.; B) 45-75% of a copolymer of ethylene and propylene containing from 45% to 70%, of ethylene and 60% or more of a fraction XSB soluble in xylene at 25° C., both the ethylene of the copolymer and XSB amounts being referred to the weight of B); wherein the amounts of A) and B) are referred to the total weight of A)+B).