A polymer composition suitable for rotomoulding comprising I) An ethylene homopolymer or copolymer with at least one other C3-10 ? olefin, having a melt flow rate of 0.5 to 30, a molecular weight distribution (Mw/Mn) of less than 4, an Mw of 50,000 to 110,000, a density of 0.940 g/cm3 to 0.970 g/cm3 and a melting point of 100 to 145.degree. C.; or I) a propylene homopolymer or copolymer with at least one other C2-10 ? olefin, having a melt flow rate of 0.5 to 30, a molecular weight distribution (Mw/Mn) of less than 4, an Mw of 150,000 to 300,000, and a melting point of 100 to 170.degree. C.; and II) an ethylene homo or copolymer with at least one other C3-10 ?-olefin, having a melt flow rate of within 40% of the melt flow rate of component (I), a molecular weight distribution of (Mw/Mn) of less than 4, an Mw of within 30% of the Mw of component (I), a density of 0.880 g/cm3 to 0.940 g/cm3 said density being at least 0.010 g/cm3 less than the density of component (I) and a melting point of at least 5.degree. C. less than that of component (I); or II) a propylene homo or copolymer with at least one other C2-10 ?-olefin having a melt flow rate of within 40% of the melt flow rate of component (I), a molecular weight distribution of (Mw/Mn) of less than 4, an Mw of within 30% of the Mw of component (I), and a melting point of at least 10.degree. C. less than that of component (I).