||Recently, bio-nanocomposite have a great attention due to increasing demand of sustainable development and eco-friendly materials. In this regard, gelatin has been considered as a prospective bio-polymer due to its biodegradability and biocompatibility. However, its utilization is limited due to its weak mechanical properties and hydrolytic stability. In this study, we developed a naturally derived, environmentally friendly, and strong biopolymer film based on gelatin reinforced by surface-modified cellulose nanocrystals (CNCs). Covalent crosslinks were formed between the amine groups of gelatin molecules and the aldehyde groups of CNCs via nucleophilic addition. The gelatin composite films developed showed an impressive improvement in terms of mechanical properties, which could also open a door for practical applications of gelatin-based materials. Also, enhanced hydrophobic properties were investigated via contact angle, wetting time, water absorption, and water solubility.