In this paper, the axial Couette-Poiseuille flow of Bingham fluids through concentric annuli is studied. Analytical solutions of different types of flow are derived Compared to previous studies, we emphasize two new types of flow, which have been missed previously, are found in our results. Hence, there are eight different forms of the velocity profile depending on values of three dimensionless parameters, which are the Bingham, axial Couette numbers and the radius ratio. Distributions of these eight forms are specified in the parameter plane of axial Couette number vs Bingham number for various radius ratios These new flow regimes are analyzed from both a mathematical and physical perspective (c) 2010 Elsevier B V All rights reserved