Two field experiments were performed during summer seasons of years 2005 and 2006 at El-Nuparia district, the desert backyard of El-Behera Governorate, to investigate the response of maize plant (Zea mays L.) hybrid of 30B9 to different growth regulators; Abscisic acid (ABA) at 30 and 50 ppm, Ethephon at 300 and 500 ppm and Cycocel (CCC) at 400 and 600 ppm, under different water stress treatments, which included missing only one irrigation  in each water stress treatment after (El-mohayah  irrigation) 10 days after germination i.e., the 2^end irrigation, the 3^rd irrigation or the 4^th irrigation beside the normal irrigation as a control treatment. Results indicated maize plants can tolerate water stress at the vegetative growth period (60 days). Missing the fourth followed by the third irrigation treatment seemed to produce more aggressive water stress for maize plants rather than those produced when missing the second and normal irrigation, respectively. Spraying growth regulators i.e. (ABA, Ethephon or CCC) on maize plants reduced significantly plant height, fresh weight and leaf area as compared to the control treatment. Vice versa, it increased significantly plant dry weight, number of leaves, total pigments, chlorophyll, free proline, endogenous abscisic acid, osmotic pressure, ear weight, number of grains, 100 grain weight, and both biological and grain yields as compared with the control treatment. Superior results were obtained by applying the higher concentrations of ABA and CCC, and lower concentration of Ethephon compared with the other treatments. Under normal irrigation conditions, it is not recommended to spray any of the studied growth regulators on maize plants for its negative effects on plant growth, productivity and chemical composition. While, under water stress conditions, applying growth regulators increased the plant tolerance to water stress which led to produce appreciated yields under these conditions after improving the physiological adaptation to water stress, yet, growth characters was declined. Higher observations under severe water stress conditions were obtained from applying abscisic acid, ethephon then cycocel at the higher concentrations, respectively.