The use of hydrogels has grown in recent years due to their ability to retain water and slowly release it to plants. This research sought to evaluate whether the hydrogel based on cashew gum interferes with the physiological performance of maize subjected to different levels of water deficit. The experiment was conducted in a greenhouse at the Federal University of Mato Grosso do Sul. A completely randomized experimental design was used in a 4x2 triple factorial scheme with 3 replications. The first factor was composed of four doses of the hydrogel: 0, 60, 120 and 240 mg pot^-1, which correspond to 7,5; 15; 30 and 60 kg ha^-1; the last factor was composed of two irrigation levels 50 and 100% of the water storage capacity. Thirty days after maize germination, gas exchange analyses were performed using a portable photosynthesis equipment (Infrared Gas Analyzer - IRGA), model Li6400XT with a photosynthetically active photon flux of 1200 μmol m^-2 s^-1 and ambient CO₂ concentration of (400 ± 10 mol m^-2 s^-1). The physiological variables evaluated were: net photosynthesis (µmol CO₂ m^-2 s^-1) and transpiration (mmol H₂O m^-2 s^-1). There was a significant interaction between hydrogel doses and irrigation levels. The use of hydrogel at any dose promotes higher values ​​of net photosynthesis and transpiration for the 50% evapotranspiration level compared to the 100% level. The results suggest that a 50% water saving combined with the use of the lowest hydrogel dose provides better physiological performance of maize plants.