Biodegradable polymer has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. The greatest advantage of these degradable polymers is that they are broken down into biologically acceptable molecules that are metabolized and removed from the body via normal metabolic pathways, for example, polylactides, polyglycolides, and their copolymers—the polymers will eventually break down to lactic acid and glycolic acid, enter the Kreb's cycle, and be further broken down into carbon dioxide and water and excreted through normal processes. Many biodegradable polymers are used as binder such as acacia, gelatin, whereas some used to coat tablets such as hydroxypropyl cellulose, polyethylene glycol, povidone and sodium carboxymethyl-cellulose., and to thicken suspensions and in ophthalmic solution as a protective colloid ,to stabilize emulsions and suspensions. . Sustained-release dosage forms employ polymers as shells for microencapsulated drugs, as erodible and non-erodible matrices, as barrier membranes to regulate the release of drugs by diffusion. The biodegradable polymer used in medical devices and controlled-drug-release applications are sterilizable and capable of controlled stability or degradation in response to biological conditions. These all play a very crucial role in enhancing the bioavailability of drug. This review covers all the aspects of biodegradable polymers in enhancing bioavailability of the drug.