This article describes the effect of compatibilising agent on natural rubber (NR)/chitosan (CS) blends. Maleic anhydride (MA) was used as the compatibiliser. The mechanical properties such as tensile strength, elongation at break, and modulus at various elongations of compatibilised NR/CS blends were studied by universal testing machine and the surface hardness was studied by Shore A Durometer. The interaction between the two components was analyzed by calculating the fraction of bound rubber in the blend from the relative weight loss data in benzene as the solvent. The incorporation of MA into NR/CS blends improved tensile strength up to 15 % of chitosan in the blend and above which it decreased. The elongations at break of the MA treated blends decreased and a drastic enhancement of surface hardness was observed by the addition of MA in the blend. The interfacial reactivity (adhesion) of NR/CS blends was studied as a function of the incorporation of compatibiliser by the estimation of relative weight loss. The data revealed an increase in the interfacial adhesion between NR and CS, resulting in an improvement of the gel fraction (%) in the blend. The effect of thermal ageing on the mechanical properties of the compatibilised blends was also studied. The morphology of the compatibilised blends was studied by scanning electron microscopy and it shows a continuous morphology.