Biopolymers are important class of materials for pharmaceutical and biotechnological applications. Studies have been carried out on different biopolymer blends and types. The area of biopolymer interactions has been the focus of intensive fundamental and applied research in recent time. Such biopolymer combinations may possess unique properties that are different from those of individual components. There is a great potential in utilizing biopolymer blends as pharmaceutical adjuvants and in controlled release drug delivery systems. Appropriate selection of biopolymer or biopolymer blend is necessary in order to develop a successful drug delivery vehicle. In drug delivery, the biopolymer blends used should be designed in such a way that their functionality remains constant throughout an application. For a successful industrial development of a viable dosage form using biopolymer blends, the biopolymers selected must be pharmaceutically approved and should also demonstrate acceptable mechanical and biocompatible properties. Biopolymer blends used in drug delivery are characterized to establish their suitability for the intended dosage form. In this chapter, biopolymer blends used in drug delivery are discussed with particular emphasis on their formation, properties, characterization, applications and their limitations and future prospects.