Chitosan is a natural biopolymer formed from chitins that considered as an effective bioregulator and elicitor in agriculture. Therefore, this investigation was done to study the effect of chitosan and chitosan nanoparticles (0 and 50 mg/l) on alleviating the adverse effect of drought stress on Lupine termis L plant. Lowering water irrigation requirement from 100% to 60%, significantly reduced different growth criteria, photosynthetic pigments, indole acetic acid (IAA), yield and its components in addition to carbohydrate, protein and oil contents of the yielded seeds of lupine plant. On the other hand, drought stress significantly increased total soluble sugars (TSS), proline and free amino acids of lupine plants, in addition to phenolic and flavonoids contents of the yielded seeds. On the other hand, pre sowing treatment with (50 mg/l) Chito or Chito NPs could increase significantly growth parameters, yield quantity and quality of lupine plant via improving photosynthetic pigments, IAA, TSS, proline, free amino acid contents comparing with their corresponding controls. However, Chito NPs was more effective than Chito. Finally it could be concluded that, the promotive role of chitosan in improving tolerance of lupine to drought stress and improve growth and yield through improving different studied biochemical processes.