The present investigation deals with the formulation, optimization and evaluation of sodium alginate based floating oral In situ gel of Pantoprazole. Sodium alginate used as a polymer and Calcium carbonate was used as a crosslinking agent. In-situ forming polymeric formulation drug delivery systems is in sol form before administration in the body, but once administered, undergoes gelation in-situ to form a gel. The formulation of gel depends upon factors like temperature modulation, pH changes, presence of ions and ultraviolet irradiation from which drug gets released in sustained and controlled manner. The objective of this study was to develop a novel in- situ gel system for sustained drug delivery using natural biodegradable polymer. The system utilizes polymers that exhibit sol-togel phase transition due to change in specific physicochemical parameters. In-situ gel was formed at a gastric pH from designed set of experiments, it was evident that formulation containing 2 % of sodium alginate control the release of drug for longer duration. The in-situ gel exhibited the expected, viscosity, drug content, pH, in vitro gelling capacity, in vitro floating ability and sustained drug release. The formulated in situ gel for Pantoprazole was found to be stable in situ gel. It was found to have better floating efficacy and in vitro release profile characteristics. Better efficiency and results of batch F-6 gives newer alternative use of natural biodegradable polymers in situ gel formulation.