AIM: To investigate the effects of sodium nitrite on spinal cord development in early-stage chick embryos. MATERIAL and METHODS: Sixty specific-pathogen-free fertile Leghorn-type eggs at Day 0 of incubation were used. Group 1 (control) received saline, Group 2 (low-dose) was administered 0.0042 mg of sodium nitrite, and Group 3 (high-dose) received 0.0084 mg. Embryonic disks were microscopically examined after 72 hours of incubation. RESULTS: In the control group, the surface ectoderm was intact, the neural tube was properly closed, and the neuroepithelium, basement membrane, somites, and notochord exhibited normal morphology. Neural tube defects were identified in seven embryos in the low-dose group and nine embryos in the high-dose group. Statistical analysis revealed that both sodium nitrite–exposed groups exhibited a significantly higher incidence of neural tube defects compared with the control group (p < 0.05). However, no statistically significant difference was observed between the low- and high-dose groups. CONCLUSION: Exposure to low and high doses of sodium nitrite induced neural tube defects in chick embryos, suggesting potential embryotoxic effects.