IN recent years several advancement has been made in research and development of Oral Drug Delivery System. Concept of Novel Drug Delivery System arose to overcome the certain aspect related to physicochemical properties of drug molecule and the related formulations. Purpose of this review is to compile the recent literature with special focus on various gastro retentive approaches that have recently become leading methodologies in the field of site-specific orally administered controlled release drug delivery. Technological attempts have been made in the research and development of ratecontrolled oral drug delivery systems to overcome physiological adversities, such as short gastric residence times (GRT) and unpredictable gastric emptying times (GET). Therefore, gastro retentive drug delivery systems (GRDDS) have been developed, which prolong the gastric emptying time. Several techniques such as floating drug delivery system, low density systems, raft systems, mucoadhesive systems, high density systems, super porous hydro gels and magnetic systems, have been employed. This review on GRDDS attempts to compile the available information with all the possible mechanism used to achieve gastric retention.