Drip irrigation system has the ability to apply water over the field uniformly. Uniformity of drip irrigation can be measured through many parameters. Uniformity is one of the procedures which should be considered in drip irrigation design and management to gain the maximum possible crop yield. The objective of this study was to investigate the effect of some uniformity parameters including Christiansen's uniformity coefficient (UC), distribution uniformity (DU), Manufacturing coefficient of variation (CV_f), and emission uniformity (EU) on crop yield and water productivity, in addition to evaluate the strength of the relationship between each of studied uniformity parameter and crop yield. Four operating pressure heads 5, 10, 15, and 20m were used to operate the irrigation system to make the required change in drip irrigation system uniformity level. The study included two crops which were lettuce and turnip. Results indicated that increasing drip irrigation system uniformity will lead to increase crop yield and water productivity of both crops. Values of correlation coefficient (r) were less than 0.5 for all uniformity parameters when correlated to crop yield. This indicated that uniformity might not be the most important factor representing the quantity of crop yield though its importance. According to the values of the (r) resulted from the relationship between each uniformity parameter and crop yield; EU had the strongest effect on crop yield. The study recommended modeling the relationship between drip irrigation uniformity and crop yield basing on EU.