Abstract: Genotoxicity of ethylicin and bismerthiazol on Vicia faba root tip cells was studied.Micronucleus assay and chromosomal aberration assay were used to determine mitotic index,micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells induced by different concentrations of ethylicin or bismerthiazol.Results show that both pesticides may induce high micronucleus frequency,mitotic index,and chromosomal aberration frequency.Micronucleus frequency increased with increasing of ethylicin concentration,and showed a linear dose-dependent manner in the treatment of ethylicin concentration ranging from 0.032 to 0.160 g·L^-1.However,it increased first and then decreased with increasing bismerthiazol concentration in the treatment of its concentration ranging from 0.625 to 2.5 g·L^-1.Different types of chromosomal aberration were induced by both ethylicin and bismerthiazol.