Multi-walled carbon nanotubes (MWNTs) were functionalized with chitosan using Cu-catalyzed Huisgen [3+2] cycloaddition click chemistry. Azide moiety-chitosan was prepared by synthesizing azide-moiety epichlorohydrin and its subsequent reaction with chitosan. Alkyne-functionalized MWNTs were separately prepared by the diazotization reaction of MWNTs with p-amino propargyl ether. Covalent functionalization of the MWNTs was accomplished through click coupling between the alkyne-derived MWNTs and the azide moiety-chitosan. The reaction was confirmed by FT-IR, Raman, SEM, and TEM measurements. Functionalized chitosan was observed by TEM on the surfaces of the MWNTs after click coupling. Electrical heating with a maximum of $6.8^{circ}C$ occurred when a voltage of 60 V was applied to the MWNT/chitosan composites, further demonstrating the chitosan functionalization of the MWNTs.