The present study delt with the teratogenic effects of sodium benzoate (SB), which is used as a food preservative and antimicrobial agent on the skeletal system of the prenatal fetuses of mice on day 18 of gestation. The used low and high doses of SB were found to be 200 and 500 mg/kg body weight. The pregnant mice were divided into four groups; control and three SB-treated groups (G₁, G₂ & G₃). Each treated group was divided into two sub-groups for treatment with low and high doses of SB. This study revealed that most elements of fetuses skull showed moderate to severe malformations. Ossification of the centra of some cervical vertebrae were absent especially at the high dose in group 2. The high dose of sodium benzoate showed some unossified caudal vertebrae especially in groups 2 and 3. The whole sternum and xiphoid cartilage became shorter than the control in all groups treated with low and high doses of SB. The cartilaginous portion of the ribs exhibited less blue colouration than the control denoting reduction in its chondrification. Also, some ribs showed curled appearance. In addition, the scapula and clavicle of the pectoral girdle were shorter and less thickened in all treated groups. The long bones of the fore and hind limbs in the high dose treated groups were shorter in length and decreased in thickness compared to those of the control. In such case, the density of red coloration was less than the control.