Background: Vitamin D deficiency is a worldwide problem associated with wide spectrum of diseases, ranging from neurological disorders to chronic inflammatory conditions. Objectives: This is a cross sectional case control study performed to compare vitamin D serum levels between full term neonates with hypoxic ischemic encephalopathy (HIE) and normal healthy neonates and to determine if there is an association between serum vitamin D levels and neonatal hypoxic ischemic encephalopathy (HIE). Patients and methods: This study included 60 full term neonates; 30 of them had the criteria of moderate to severe HIE encephalopathy and the others is clinically free. We measured the serum levels of vitamin D using ELISA in both groups and the mothers of diseased neonates. Results: Neonates with hypoxic ischemic encephalopathy had a significant lower (25(OH) vitamin D) than controls (P-value ≤ 0.001), half of them (50%) had deficient levels of vitamin D, 23.3% had insufficient levels and 26.7 had normal levels of vitamin D. The control group had normal level in 90% and only 10% had insufficient levels of vitamin D and there were significant lower levels in serum maternal vitamin D below normal. Conclusion: Full-term neonates with HIE had lower serum levels of vitamin D than healthy neonates with positive correlations between neonatal serum vitamin D levels and their maternal levels.