The effects of gaseous ozone treatment on microbial counts and shelf life of  chilled boneless chicken breasts as well as the influence of ozone on chicken quality properties such as color, odor, and texture were studied. Treatment of chicken breasts with 40, 60, and 70 ppm of gaseous ozone for 20 minutes efficiently reduced the populations of Total aerobic bacterial count, Coliforms, and Total mould counts and prolonged the shelf life of the chicken breasts more than 9 days. Immediately after ozone treatment panelists were unable to detect any color, odor or texture differences between the ozonated and control groups but with storage time ozonated groups seemed to had better quality as compared with non-ozonated group. Thus, at the ozone concentrations and exposure times used in this study, ozone effectively reduced the population of spoilage bacteria contaminating the chicken breasts yet had no adverse effects on their quality characteristics.