A method was developed for synthesis of chitosan-monoterpenes nanoparticles (Ch-M-NPs). Four monoterpenes; limonen (M1), linalool (M2), minthol (M3) and thymol (M4) have been used for the synthesis of four different types of nanoparticles. Scanning electron microscopy showed that, the shape of Ch-M-NPs was spherical and the mean of particle size ranged between 33.67 to 54.19 nm. The zeta potential values ranged between -.03 to -0.169 mV. The antimicrobial activity of prepared nanoparticles was evaluated. The estimated MIC values against E. coli and Salmonella typhimunium showed that Escherichia coli was more susceptible to chitosan, monoterpenes and/or chitosan-monoterpenes nanoparticles than S. typhimunium. Among the monoterpens, M1 was the most active (MIC = 350 and 450 mg/L against E. coli and S. typhimunium, respectively) and M3 was the lowest active (MIC =1600 and 1800 mg/L). Among Ch-M-NPs, Ch-M1-NP was the most active (MIC=180 and 250 mg/L against E. coli and S. typhimunium, respectively) and Ch-M3- NP was the lowest active nanoparticles (MIC =450 and 500) against E. coli and S. typhimunium, respectively). The antibacterial activity against E.coil in minced beef meat samples treated with chitosan (Ch), monoterpens (M), chitosan- monoterpens nanoparticles (Ch-M-NPs) after storage for ten days at 4^oC expressed as 10⁴cfu/g showed that M1 was the most active through the different time of experiment (79.33 and 40.00 cfu/g) at concentrations of 1000 and 2500 ug/g. However, M2 was the lowest active (125.83 and 80.00 cfu/g) compared with control+ and control- (˃300 and 243.67 cfu/g, respectively). Moreover, the antibacterial effect of Ch-M-NPs was greater compared with crude monoterpenes. The Ch-M1-NP was the most active (18.17 and 8.33cfu/gm) and Ch-M3-NP was the lowest active (35.83, 18.00 cfu/g). The results suggest that Ch-M-NPs could be used in minced meat preservation as antimicrobial agents and for shelf-life extension.