We have investigated the genotoxicity of 1, 2, 4-trimethylbenzene using Ames reverse mutation test. In Ames reverse mutation test, 1, 2, 4-trimethylbenzene treatment at the dose of 100, 50, 25, 12.5, 6.25 ㎍/plate did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA 1537 and in Escherichia coli WP2uvrA with and without metabolic activation. These results indicate that 1, 2, 4-trimethylbenzene has no mutagenic potential under the condition in this study.