This paper considers certain aspects involved in the anodizing of extruded 6063 aluminium profiles where difficulties in controlling the uniformity of the anodic oxide film thickness formed on the work-piece surfaces can often arise. Applied current, electrolyte conditions and circulation in the electrolyte bath are three of the key factors that must be controlled to ensure required conditions for anodizing. In this work a model based on three dimensional flow analysis was used to simulate the flow behaviour of electrolyte in the electrolyte bath. The study focused on the effect of variations in flow patterns in the electrolyte bath on the anodized film thickness at selected representative areas of the work-piece, particularly at the corners of complex design profiles. Three extruded profiles were selected for the study under anodizing conditions designed to give anodic film thickness of 8-10 microns: these were a current density of 6,000-7,000 amp/m2, a voltage of 19 Volt and an anodizing temperature of 20oC. The results obtained indicated that different flow conditions and flow rates affected the thickness of the anodic film which was measured by metallography at various positions on the extrusion profiles.