Mucoadhesive drug delivery systems interact with the mucus layer covering the mucosal epithelial surface, and mucin molecules and increase the residence time of the dosage form at the site of absorption. Mucosal adhesion is backed by several theories which include electronic, adsorption, wetting, diffusion, fracture and mechanical. Stages of mucoadhesion include contact stage and consolidation stage. Mucoadhesion while considering drug delivery is having several merits, because of the ideal physiochemical characters of the mucosal membrane. Ideally a mucoadhesive dosage form interacts with the mucosal membrane by ionic bonds, covalent bonds, Van-der-Waal bonds and hydrogen bonds. Various sites for mucoadhesive drug delivery system are ocular, nasal, buccal cavity; GIT, vaginal, rectal and several specific dosage forms have been reported. Factors affecting mucoadhesion are molecular weight, flexibility of polymer chain, pH, presence of carboxylate group and density. Several synthetic and natural polymers are identified as suitable candidates for mucoadhesive formulation. Ex-vivo/in-vitro studies utilizing gut sac of rats provides indepth knowledge about the adhesive property of the dosage form as well as polymers. AFM can be used as a part of imaging methods. Mucoadhesive drug delivery system shows promising future in enhancing the bioavailability and specific needs by utilizing the physiochemical characters of both the dosage form and the mucosal lining. It has to be noted that only a moist surface can bring the mucoadhesive nature of the dosage form.© 2017 iGlobal Research and Publishing Foundation. All rights reserved.