Chitosan is a polycation biopolymer material. It has several applications, especially in the biopharmaceutical and biomedical fields. Chitosan was produced from shrimp waste by chemical method involving demineralization, deproteinization and deacetylation. It was characterized by intrinsic viscosity measurement and Fourier Transform Infra-Red in order to determine the average molecular weight and degree of deacetylation of purified Chitosan. Chitosan was modified by grafting process with maleic anhydride, poly(adipic anhydride) and poly(sebacic anhydride) to evaluate their effect on binding to the human genomic DNA. The grafted chitosan derivatives appeared as promising materials to be used as a model for DNA and gene delivery. Grafted chitosan-DNA complexes were determined by gel electrophoresis technique and ultraviolet spectroscopy.