The present disclosure provides a polyolefin composition made from or containing: A) from about 60 to about 89% by weight based upon the total weight of the polyolefin composition of a copolymer of butene-1 with ethylene having a copolymerized ethylene content of up to about 18% by mole based upon the molar composition of the copolymer, and no melting peak detectable at the DSC at the second heating scan; and B) from about 11 to about 40% by weight based upon the total weight of the polyolefin composition of an ethylene polymer having density of from about 0.900 to about 0.970 g/cm3, measured according to ISO 1183 at 23° C.; wherein the amounts of A) and B) are referred to the total weight of A)+B) and the DSC second heating scan is carried out with a heating rate of 10° C. per minute. The composition is useful for preparing gaskets.