A masterbatch composition, a polyolefin composition prepared from the masterbatch and articles prepared from the polyolefin composition. The masterbatch contains (percent by weight) from 20% to 90% of A) a crystalline polypropylene containing from 25% to 75% of a fraction AI having a melt flow rate MFRI of from 0.5 to 10 g/10 min., and from 75% to 25% of a fraction AII having a melt flow rate MFRII such that MFRII/MFRI is from 30 to 2000; and from 10% to 80% of B) a copolymer of ethylene and at least one C3-C10 null-olefin, the copolymer containing from 10 to 70% of ethylene, the copolymer being soluble in xylene at room temperature, and having an intrinsic viscosity nullnullnull of from 4 to 9 dl/g. Articles prepared from the polyolefin composition exhibit a good balance of physical properties and reduced surface defects such as tiger striping.