One of the concerns regarding the common use of genetically modified (GM) feed in animal nutrition is that transgenic sequences may have a negative effect on the organism or (and) its cells. The present report assesses the genotoxic potential effect of a diet containing GM triticale on mice by using micronuclei test and comet assay. One group of mice (C57 Bl/6J strain) were fed continuously over five generations a pelleted diet containing 20% of GM triticale (tolerant to phosphinothricine) grain, while the control group was fed pellets with 20% conventional triticale grain. Ten 91-days-old mice (five females and five males) were randomly selected from each group and each generation for micronuclei test in bone marrow and peripheral blood erythrocytes and the some number of mice was used for comet assay. The results obtained did not reveal any statistically significant differences in the micronuclei frequency nor any other DNA damage between the control and experimental groups of mice in all five generations. Thus, it seems evident that the diet containing GM triticale (with bar transgene) does not induce chromosome damage, nor has it any effect on the formation of DNA breaks or base lesions.