Fresh vegetable juice is a non-heat treated product and the only step to reduce microbial growth is washing. Therefore, the materials for fresh vegetable juice including Angelica keiskei, Brassica loeracea var. acephala, and Daucus carota L. were treated by ozone after the first washing process and investigated for microbial and chemical changes. The number of the total aerobic bacteria in materials after selection step were $8.2{ imes}10^5{sim}5.0{ imes}10^6;CFU/g$, which was a higher contamination level than the limit of Korea food code ($10^5;CFU/g$). However, after the 1st washing process and ozone treatment, the total aerobic bacterial number was reduced to $4.7{ imes}10^4{sim}6.7{ imes}10^4;CFU/g$, which showed 2 log microbial reduction. After the 2nd washing step followed by ozone treatment, there was no difference in microbial number. The number of colifroms in the materials of fresh vegetable juice were $8.0{ imes}10^3{sim}3.5{ imes}10^3;CFU/g$ initially but showed $1.5{ imes}10^2{sim}3.0{ imes}10^2;CFU/g$ after the ozone treatment (1 log reduction). On the other hand, there was no changes in the contents of ascorbic acid, flavonoids, polyphenols, minerals (cadmium and lead) during all processes. In addition, no color changes were observed during washing process. Therefore, ozone treatment in the materials of fresh vegetable juice decreased the microbial numbers. Also, chemical characteristics of ozone treated sample were not different when compared with control.