In a preceding work, we have established relationships between the conditions of sharkskin onset and the rheological and molecular properties of the extruded polymer. Based on this approach, we propose now to define a molecular criterion, able to discriminate the ability of linear polymers to give rise to sharkskin in extrusion. The validity of this criterion is experimentally verified for a certain number of polymers, using data taken in the literature. (C) 2006 Elsevier B.V. All rights reserved.