This study aimed to examine the impact of different concentrations of chitosan (0, 25, 50, 100, 150, 200, 250, 300, and 400 mg.L-1) on the protein profile of lupine plants over a 45-day cultivation period. A pot experiment was conducted to grow lupine seeds treated with chitosan. After 45 days, the leaves were extracted, and protein banding patterns were analyzed using the SDS-PAGE technique. Protein number and protein intensity were modified in relation to the corresponding control. Among the 15 protein bands, the highest protein weight was 169 kDs, whereas the lowest protein weighed 11 kDa. The 19 kDa protein, known as pathogenesis-induced protein (PR-10), was identified in response to 250, 300, and 400 mg.L-1. Furthermore, there was a significant accumulation of γ-conglutins and δ-conglutins, weighing 12 and 13 kDa, respectively. The presence of high chitosan concentrations resulted in the absence of the 23 kDa structural protein. Chitosan modulates protein structure to promote growth and enhance defense against pathogens and environmental stress. We suggest using chitosan for agricultural lands that have been adversely affected by the overaccumulation of chemical fertilizers.