Self-nanoemulsifying Drug Delivery system (SNEDDS) is isotropic mixture of natural or synthetic oil, surfactants and co-surfactants. The present work is to prepare, characterize and optimization of Self nano emulsifying drug delivery system containing Anti-asthmatic drug. The SNEDDS of Montelukast sodium is prepared by probe Sonication method using span 60 as surfactant, Eudragit RL 100 and Eudragit RSPO as components and PVA as Co-surfactant. They are characterized for FTIR studies, SEM study, particles size analysis and drug entrapment efficiency and they are evaluated for visual assessment, self emulsification time, Robustness to dilution, in-vitro dissolution studies and stability studies. The FTIR spectra’s of SNEDDS are compatible with each other without any drug polymer interaction The prepared nanoparticles are smooth in surface and showing spherical in shape. The average particle size of the nanoparticles was found in the range of 315 nm to 513 nm. The drug encapsulation efficiency (DEE) of the SNEDDS was found in the range of 77.58% to 93.26%. By the visualization study all the formulations are found to be Grade III. Self emulsification time is found to be within 1 minute. Phase separation or no precipitation indicating the stability of nano emulsion. The in-vitro drug release data of all the formulations were found to be controlled release over a period of 24 hr. The short time stability study of optimized formulations has done and subjected to drug encapsulation efficiency and in-vitro drug release studies, where results shown that there is no significant change in the formulation.