The single-screw extruder is commonly used in polymer processing where the performance of the mixing section is significant in determining the quality of the final product. it is therefore of great interest to simulate the flow field in a single-screw extruder. In this paper simulations of non-Newtonian fluids in a single-screw extruder are performed using the lattice Boltzmann model. (c) 2007 Elsevier Ltd. All rights reserved.