Biopolymer-based nanocomposites have gained significant attention in biomedicine due to their unique properties and potential applications. These nanocomposites combine biopolymers, natural polymers derived from renewable sources, with nanoparticles or other nanoscale materials to create materials with enhanced properties and functionalities. Biopolymers that are used to make bio-nanocomposites are cellulose, alginate, chitosan, starch, polylactic acid (PLA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), etc. These have different properties, and they can be used in several types of treatments. Scaffolds frequently employ polylactic acid-gelatin, nanocellulose, and chitosan. Studies have shown that some special types of hydrogel films have proven beneficial in anticancer treatment. Synthetic and naturally occurring substances such as PLA, polyvinyl alcohol (PVA), guar gum, and chitosan are employed in the drug delivery system. Nanocomposites such as silver nanoparticles with chitosan, sulfated polysaccharides, and thyme-loaded carrot nanocellulose or starch biopolymer nanocomposites have been used to stop bacterial development. This review article provides a comprehensive insight into biopolymer-based nanocomposites and their uses. Also, it has been incorporated into fields such as biosensors, bioimaging, blood clotting, immunomodulation, antibacterial and antiviral drugs, and food packaging. Hence, the primary objective of this review is to provide an overall perspective on biopolymer nanocomposites in nanomedicine.