A parametric study was conducted in order to reduce the pressure drop and to improve the uniformity of flow distribution in a symmetric flow distributor. A CFD model was employed to simulate the flow behavior by solving the Navier-Stokes equations in a complete 3D model. The present work is a complete parametric study of a base model, reported in previous studies, but keeping the same flow pattern. To improve the performance of the base design, three known successive parametric ratios, as functions of the hydraulic diameters of the channels, were tested in order to study the advantages and disadvantages of each one in terms of two dimensionless parameters that measure the uniformity of flow distribution. A remarkable improvement in the performance of the base model was achieved by modifying the width ratio of the channels. The present work is a contribution to the study of flow distributors to be used as heat exchangers, PEMFC flow channels and other flow devices.