Accelerating global warming and water scarcity and improving water use efficiency are considered essential factors for achieving adequate crop development and productivity. Therefore, the authors targeted the use of arbuscular mycorrhizal fungi (AMF) and Pseudomonas fluorescens (Ps1) for improving growth, productivity, and water use efficiency of broccoli plants (Brassica olercea L. var. italica, cv. Belstar F1) under various irrigation regimes i.e., 50, 75, and 100% of crop evapotranspiration (ETc). Two greenhouse experiments were carried out in clayey soil. The combined inoculation of endomycorrhizae and Ps. fluorescens (Ps1) improved water use efficiency and consequently vegetative growth and yield. Under the applied irrigation regime 75% ETc of broccoli inoculated with both endomycorrhizae and Ps. fluorescens (Ps1) showed higher head weight (616 and 647 gram) than those grown under the irrigation regime 75% ETc combined with endomycorrhizae (568 and 559 gram) during the two seasons, respectively. However, a minimum yield value of 149 and 142 grams per plant was recorded for un-inoculated plants grown under 50% irrigation regime during both seasons. In conclusion, the combined inoculation with endomycorrhizae and Ps. fluorescens (Ps1) under irrigation regime 75% ETc was the optimum combination for increasing water stress resistance and broccoli productivity under water scar-city circumstances.