Background: Vitamin D deficiency in pregnancy is associ-ated with wide ranging clinical outcomes, including obstetric complications, preterm birth and adverse offspring outcomes affecting the skeletal, immune and respiratory systems.Vi-tamin D may have a role in immune tolerance in a pregnant woman, to prevent fetal rejection. Vitamin D travels to the fe-tus by passive transfer and the fetus is entirely dependent on maternal stores. Therefore, it is essential to know vitamin D level during antenatal period to prevent adverse outcomes. The association of maternal vitamin D deficiency with asthma and impaired lung function in offspring were described by some authors. Aim of Study: The aim of this work is to assess maternal vitamin D status and its association with pregnancy outcomes. Patients and Methods: Prospective observational cohort study was designed on 80 pregnant women 18-38 years with singleton pregnancy attended Obstetrics and Gynecology De-partment at Mansoura University Hospital from May 2022 to May 2023, with no medical disorders or history of vitamin D intake during pregnancy. Chronic diseases as liver diseases and severe infections or take corticosteroids were excluded. Results: There was statistically significant association between maternal vitamin D level and gestational DM (p= 0.023), while, no statistically significant association between maternal vitamin D and neonatal outcome was found. The ma-jority of the pregnant women, 73.8% were vitamin D insuf-ficient, 11.2% were vitamin D deficient and 15% had sufficient vitamin D level. The mean value of the maternal vitamin D level was 19.17±8.78ng/ml and the mean value of fetal vitamin D level was 15.51±7.80ng/ml. Infants were divided into: in-sufficient group 58 (72.5%), deficient 16 (20%) and sufficient groups 6 (7.5%). There was highly statistically significant cor-relation between maternal and fetal vitamin D level. Conclusion: Our study suggests that vitamin D deficiency in pregnant women and their infants is still a serious health problem. However, there were no statistically significant asso-ciations between maternal vitamin D and both maternal & neo-natal outcome except maternal gestational diabetes mellitus. Recommendations: Routine measurement of maternal se-rum vitamin D can be advised to become an integral part of the antenatal care protocol. VD supplementation can be subse-quently added to carefully selected groups to decrease the risk of multiple adverse maternal and neonatal health outcomes including gestational DM, preeclampsia, primary cesarean section, abortion, fetal intrauterine growth restriction, risk of preterm birth, low birth weight, and neonatal hypocalcemia.