To retain the fresh taste and flavor of Kimchi, ozone treatment was applied for kimchi food materials. In this study, Chinese cabbage and salted Chinese cabbage, the highest portion of Kimchi materials, were treated by ozone ($3{sim}9$ ppm) and their microbiological and chemical characteristics were investigated. Initial number of total aerobic bacteria of Chinese cabbage and salted Chinese cabbage were $1.3{sim}10^7$ and $7.1{sim}10^6$ CFU/g, respectively. However, when ozone was treated, the number was decreased and this decrease of bacterial number was maintained during storage. Yeast and mold populations were $6.0{ imes}10^3$ and $1.2{ imes}10^3$ CFU/g in Chinese cabbage and salted Chinese cabbage, respectively; however, an ozone treatment also decreased the yeast and mold populations. Other physical and chemical characteristics of ozone treated sample such as color, hardness, contents of ascorbic acid and reducing sugar of Chinese cabbage and salted Chinese cabbage were not different when compared with control.