Bionanocomposites are a promising class of hybrid materials made from natural and manmade biodegradable polymers with organic and inorganic fillers that have emerged with varied scope of promising bioapplications in fields like tissue engineering, drug delivery, gene delivery, wound healing, anti fouling and other biotechnological fields. In order to design and develop them, a thorough understanding of their structure, properties, polymer-matrix interaction, and additional modifications based on fundamental requirements is required. As a corollary, the assessment of biological interactions and the management of physical and chemical properties are crucial for their potential uses. This chapter emphasizes on the use biopolymer based composites in the medical and pharmaceutical field.