Two field experiments were conducted in a sandy soil in the extension field in El-Kassasein, Ismailia Governorate, Egypt during 2007 and 2008 summer seasons. The work aimed to study the effect of five levels of glycinbetaine (0, 5, 10, 15, 20mM/fad) on the response of SC 10 maize hybrid to three rates of drip irrigation water (1.00. 0.80 and 0.60 of the estimated crop evapotranspiration, which represented 2625, 2100 and 1575 m3water/fad, respectively). The most important findings could be summarized as follows: Irrigation by 1575 m3/fad instead of 2625 m3/fad reduced significantly ear leaf blade area, total chlorophyll, relative water content and leaf water potential, except the content of GB in leaves which was significantly increased in both seasons. Meanwhile, increasing the level of glycinebetaine (GB) up to 15 mM/fad increased these traits and the content of GB in leaves compared with their untreated analogues. Decreasing the amount of irrigation water from 2625 to 1575 m3/fad reduced significantly the grain yield, protein yield and water use efficiency (IWUE). While, the relative increase percentages due to application of 15mM GB/fad compared with zero GB were 28.47 and 25.30%, 54.53 and 47.25%, and 27.61 and 25.10% for these traits in both seasons, respectively. The interaction between both studied factors showed that under moderate water stress condition (2100 m3/fad) without GB addition the responses of these traits were only 11.59 and 10.77 ardab/fad, 135.29 and 119.69 kg/fad and 0.773 and 0.718 kg m-3 compared with 14.31 and 13.49 ardab/fad, 195.07 and 176.25 kg/fad and 0.954 and 0.899 kg m-3 when the concentration of GB was increased to 15mM GB/fad in both seasons, respectively.