In the field of dynamics for a dusty fluid, the volume of the dust particles and flow behaviour of particles in different conditions is very important in engineering problems such as atmospheric fallout, nuclear reactor, powder technology, performance of solid fuel rocket nozzles, air craft icing and so many others. An analysis is presented in this paper to study the effects of thermal dispersion and Viscous dissipation on unsteady flow of a viscous incompressible dusty gas through a hexagonal channel of uniform cross section under the influence of magnetic field and time dependent pressure gradient. The results show the change in velocity profile of gas and particles in the presence of magnetic field with time, thermal dispersion and volume fraction phi. (C) 2003 Elsevier Science Ltd. All rights reserved.