Abstarct: In the present study, encapsulation by chitosan (CS) and benzoic acid (BA) nanogel was used to improve antioxidant and antimicrobial activity and stability of the Rosmarinus officinalis essential oils (REOs). The mean diameter of the gel nanoparticles was under 100 nm that had uniform size with spherical shape. The Results of radical scavenging activity of the nanogels revealed that antioxidant compounds of nano-encapsulated were slowly released. Subsequently, the antibacterial activity of the coatings that have free REOs and CS–BA nanogel-encapsulated REOs against Salmonella typhimurium was evaluated on inoculated beef samples. The results showed that the CS–BA nanogel-encapsulated REOs coating was more effective than the free REOs in reduction of Salmonella typhimurium population on beef under cold storage. Nano-encapsulation at 2 mg/g beef had the most promising effect on reduction of the pathogens population. Moreover, nano-encapsulation caused the least effect on increasing of pH of beef samples. CS–BA nanogel-encapsulated REOs at 0.5 mg/g beef had minimum effects on the color values during the storage. The results indicated that due to the volatility and instability of the EOs when it exposed to the environmental factors, their encapsulation caused considerably to improve physico- chemical characteristic. In conclusion, REOs in form of nanogel can be used as an effective method to reduce food borne pathogens like S. typhimurium and improved of the meat shelf life.