Signal molecules such as calcium (Ca2+) and chitosan play an essential role in alleviating drought negative impacts on various plants. To investigate the effects of calcium carbonate (Ca2+) and chitosan at concentrations of 0, 20, 40, and 60 mgL-1on growth, some biochemical and physiological aspects, also, seed yield and quality of peanut in water stress. The current work was performed in two field trials at two summer seasons of 2022 and 2023 in the National Research Centre (NRC) experimental farm, Al Nubaryia district, El-Behaira Governorate, Egypt. The results showed that, growing peanut plants under low irrigation water (I75%) resulted in significant reduction in growth criteria (shoot length, branches number /plant, shoot fresh and dry weight/plant), photosynthetic pigments components and endogenous indole acetic acid levels as well as yield components (branches & pods number /plant, pods & seeds yield /plant, biological yield/plant,100-seeds weight, pod & seed yield (kg/feddan), as well as comparing by untreated plants (I100%). Reversal magnitude was reported when normal irrigation treatment I100 was applied. Normal irrigation improved significantly root length, fresh & dry weight as well as total soluble sugars (TSS) and proline contents. Calcium carbonate and chitosan exogenous treatments at various concentrations enhanced peanut growth & yield. Additionally, increased the nutritional contents in seeds such as carbohydrates, protein, and oil percentages. In conclusion, calcium carbonate and chitosan have an improving influence on mitigating negative impacts of drought stress on peanut plant productivity under new sandy soil, exogenous applications of 60 mgL-1 CaCO3 or chitosan under water stress increased peanut productivity by 21.1 and 39.4% and saving 25% from irrigation water consumption compare with the control of 100 % well watered.