The flow uniformity among individual branches within a manifold system can be a significant factor to predict the performance and efficiency of various engineering applications. The non-uniform flow within the manifold system occurs due to the development of vena-contracta at the inlet to the tubes. In order to reduce the flow mal-distribution in the header-lateral system, an approach is presented in this paper. In this approach, the inlet to the lateral pipe is arranged such that the flow enters the lateral pipe with a velocity vector inclined at a certain angle with respect to the cross section of the manifold. Two test sections representing two header structures were used in this study. The first test section is conventional manifold, the second is a modified manifold (the lateral pipes of manifold were tilted a certain angle with axis of manifold). In both test sections, the diameter of the main pipe was 101.6 mm and of the lateral pipe was 50.8 mm. The results of this study showed that the method of changing the angle of water entry to lateral pipes in order to obtain uniform flow has improved the flow distribution by 54% at entry angle of 60, that is a reduction in absolute stander deviation from (0.481) to (0.136) and the maximum ratio between highest and lowest flow is 26%. Also, the change in the total flow rate has a slight effect on flow uniformity.