Bionanohybrid are produced by accumulating biologically derived polymeric species or molecules with inorganic substrates through interactions at the nanoscale. This method is important to the synthesis of materials that symbolise emerging, multidisciplinary topic at the association of material sciences, life sciences and nanotechnology. These substances are of huge attention due to many applications in imperative domains containing regenerative medicine and new materials synthesis having improved functional and structural properties. The understanding of characterization and functionalization of bionanohybrid is crucial for further enhancement in application of these materials in various application like waste water treatment. Therefore, this chapter focus on characterization of bionanohybrids through various techniques based on analysis of composition, size, morphology and functionalization. Along with this, it also provide the in-depth knowledge on the functionalization of bionanohybrids which includes methods of functionalization, activation of functional groups and factors affecting the bionanohybrids. This chapter will be beneficial to the readers for accomplishing comprehensive knowledge about characterization and functionalization of bionanohybrids.