Three-carbon chemicals (chlorinated and nonchlorinated, saturated and unsaturated, hydroxy- and oxo-hydrocarbons) were assayed for genotoxicity. The sister chromatid exchange test in vitro served as the test system. Without S9 mix, the nonchlorinated solvents 1-propanol, 2-propanol, and 2-propanone (acetone) did not increase the SCE frequencies. All chlorinated 3-C hydrocarbons, except 1,2,3-trichloropropane, proved to be potent SCE inducers in V79 cells without S9 mix. In the presence of S9 mix, the results obtained with the nonchlorinated solvents were also negative, whereas 1,2,3-trichloropropane was transformed to SCE-inducing metabolites. The addition of S9 mix resulted in an increased SCE rate for 2,3-dichloropropanol, whereas genotoxicity of 2,3-dichloropropene, 1,2-dichloropropane, 1,3-dichloropropene, and 1,3-dichloropropanone was reduced. 1,3-dichloropropanol, 1,3-dichloropropene, and epichlorohydrin were substantially inactivated by S9 mix in the V79/SCE test. It can be concluded that the reactivity of the saturated dichloro compounds in the SCE test depends on the degree of oxidation. There is no general difference between the reactivity of alpha, beta-dichloro and alpha, omega-dichloro compounds.