This paper reports a computational study using CFD on a hot gas filter in cross flow arrangement. The filter generally operates with the dirty gases passing through the filter elements, the particulate material being deposited on the outside of the filter. However, in power co-generation plants, hot gas filtration is needed to allow the hot exhaust gases to be fed to a turbine without causing any physical damage to the blades. The aim of this work is to increase understanding of the deposition process and the factors that affect the build up of the filter cake. A parametric investigation is undertaken with particular emphasis on the effects of the ratio of the approach cross flow velocity to filter face velocity on the deposition pattern as a function of the particle size (1 to 100 microns). Velocity fields and particle tracks are presented, in addition to the radius of convergence which is a parameter that characterizes the deposition process for each flow regime.