The major challenge for any drug delivery system is the attainment of effective bioavailability without affecting the protective physiological mechanisms within the body. Systems based on mucoadhesive polymers have been widely preferred as these polymers not only prolong the residence time of the system on mucosal surfaces, but also retarded drug elimination. Mucin is one of the prominent targets to improve drug retention by enhancing adhesion between polymer and mucus membrane. Thiomers are modified mucoadhesive polymers that possess thiol bearing side chains display enhanced mucoadhesion that could be attributed to the formation of disulfide bonds between thiolated polymers and cysteine-rich subdomains of mucus glycoproteins. This review proposes the potential of thiomer as a promising and effective carrier for delivery of therapeutics. (C) 2013 Elsevier Ltd. All rights reserved.