A study was performed to investigate the effect of ozone on the inactivation of Listeria monocytogenes when applied on solid media. Suspensions of L. monocytogenes ranging from 107 CFU/mL were inoculated onto selective medium, subsequently exposed to ozone in gaseous phase. The relationship between ozone concentration and treatment duration produced efficient changes in colony-forming units (CFU). Gaseous ozone effectively inactivates L. monocytogenes at concentrations of 0.55mg/Sec during short exposure times 30-300 seconds. Scanning electron micrographs were taken to examine the inactivation of bacterial cells. Weibull function was applied to predict the optimal ozonation duration required for the complete inactivation of L. monocytogenes. Accordingly, direct ozone diffusion treatment could be used as a prospective option to disinfect Listeria populations present in any solid medium.