Abstract. In this study, the effects of sodium benzoate (E-211) (SB) on the liver tissues of chicken embryos which were exposed to different doses of SB and for different durations were histopathologically investigated. SB was injected into vitellus at three different doses (250, 500, 1000 mg/kg) on the 5 th day of the incubation. The embryos of the control and experimental groups were collected on the 7 th day (stage 31) and 10 th day (stage 36) of incubation and weighed. It was statistically detected that SB caused rise to a significant decrease (P<0.001) on the total weights of the embryos depending in the dose and duration. At microscopic level deterioration of vein structures, congestion, edema, sinusoidal dilation, deterioration of hepatocyte arrangements, swelling, vacuolization, chromatin condensation, karyolysis, shape deformation and eccentric located of the nuclei decrease in Nuclear Organization Regions (NOR) and mitotic division, stickiness of chromosomes, anaphase bridge, nuclei budding and the formation of micronuclei were observed.