Abstarct: The aim of this study was to examine black seed oil in water Pickering emulsion stabilized with chitosan (CS)-stearic acid (SA) nanogel, and to investigate oxidative stability by using rosemary essential oil (REO) as a deterrent to the oxidation at the first step, various proportions of SA to CS, CS-SA nanogels were supplied by using the self-assembled method to get a appropriate structure of nanogels. The results of scanning electron microscopy (SEM) images showed that the uniformity of particles was relevant to raise a ratio of SA to CS content. Subsequently, the effect of pH (2, 5, 8, 10 and 12), SA to CS (0, 25, 50 and 75%) and oil to nanogel ratio (1, 5, 10 and 20) on the size of oil droplets and the stability of the emulsions at the 3 hours and the seventh day were investigated. The results showed that the highest stability and minimum droplet size was achieved when sample was run in the flowing condition: pH 8, SA to CS ratio of 75% and oil-to-nanogel ratio of 10. Afterward, the oxidative stability of the pickering emulsion prepared in optimal condition, with using the REO either in shell and core nonogel at 200 and 1000 ppm was evaluated by peroxide and thiobarbituric acid method during 19 days at 45 °C. Much more stability was observed when REO was used in the shell of oil droplets instead of the oil core. The results of this study showed that REO in black seed oil in water pickering emulsion had a critical role in the improving of physical and chemical stability.