Abstract Background: Vitamin D is a steroidal prohormone that plays a significant role in calcium and phosphate metabolism. It reaches the body through synthesis in the skin or through food ingestion. The metabolites of this vitamin play key roles in metabolism of minerals. Requirement for calcium increases in 3rd trimester of pregnancy and for this reason it is vital to receive adequate vitamin D and calcium during pregnancy for fetal homeostasis. Aim of Study: The objective of this study was to discuss the relation between maternal vitamin D level in pregnancy and development of low birth weight neonates. Patients and Methods: This was a prospective cross-sectional study conducted on 60 pregnant female presented to Obstetrics and Gynecology Department of Damanhour Teaching Hospital during the period from November 2019 till November 2020 and were classified into group (A) and (B) each included 30 neonates (A) with birth weight <2500 gm and (B) with birth weight >2500gm. Data were fed to the computer using IBM SPSS software package version 20.0. Results: Our results revealed a non-significant statistical difference between both groups regarding demographic data of women. Also, there was a significant correlation between the level of vitamin D deficiency and the development of of low birth weight and the vitamin D categories and fetus weight either low or normal birth weight. Conclusion: We can conclude that Vitamin D supplemen-tation during pregnancy is essential to help in normal devel-opment of the fetus and prevent fertal growth retardation (FGR).