In order to evaluate the mutagenic potential of Typhoid vaccine, 3 sets of mutagenicity tests were performed. In the reverse mutation test using Salmonella typhimurium TA98, TA100, TA1535 and TA1537, Typhoid vaccine did not increase the number of revertant at the doses of 100, 50, 25, 12.5, 6.25 $mu extrm{g}$/plate. I n chromosome aberration analysis using CHO cells were not found chromosomal aberration in different concentrations with or without metabolic activation at the doses of 0.25 mg/ml, 0.5mg/ml, 1mg/ml. In mouse micronucleus test, no significant increase in the occurrence of micronucleated polychromatic erythrocytes was observed in ICE male mice intramuscularly administered with Typhoid vaccine at the dosed of 0.1 mg/ml, 0.5 mg/ml, 1mg/ml. These results indicate that Typhoid vaccine gas no mutagenic potential in these in vitro and in vivo systems.