Controlled drug release system is one of the most favourable technique of novel drug delivery system owing to its reproducibility and ease of formulation. Nanotechnology is very useful for controlling the drug release and thus improving the pharmacokinetic and pharmacodynamic properties of the drug. The technique improves patient compliance by reducing both dose and the frequency of administration and thus minimizing the local as well as systemic toxic effects. The aim of the present research work was to formulate and evaluate gastroretentive nanoparticles of Repaglinide, an anti-diabetic drug by using the ionotropic gelation method. Repaglinide has a very short half-life of 1 hour with bioavailability 56%. Sustained release mucoadhesive nanoparticles of Repaglinide were prepared to increase the drug residence time in gastrointestinal tract and thus improving the bioavailability of drug. The mucoadhesive nanoparticles were prepared by using chitosan and sodium alginate as polymers; calcium chloride as the crosslinking agent. Different formulations were prepared with varying concentrations of chitosan and sodium alginate in order to achieve the optimum particle size and maximum encapsulation efficiency. The particle size of nanoparticles was found to be in the range of 300 nm to 756 nm. Drug encapsulation efficiency ranged between 56% to 80% with controlled drug release upto 88% in phosphate buffer pH 7.4 and 75% drug release in 0.1N HCl in 12 hrs. FT-IR and DSC studies showed that the drug and polymers were compatible. The results of swelling study and bioadhesive strength indicated that optimized formulation exhibited excellent mucoadhesive properties