Introduction: Low Vitamin D levels in pregnancy have been associated with an increased risk of gestational diabetes, pre-eclampsia, bacterial vaginosis, preterm birth, disordered fetal skeletal homeostasis, and impaired offspring lung health. As a result, current public health advice in several countries is to universally supplement Vitamin D during pregnancy. Data regarding the Vitamin D levels of the ethnic obstetric population in Kenya are not available; hence recommendations for Vitamin D supplementation have no scientific basis. Objectives of study: This research was carried out to determine the prevalence of deficiency of Vitamin D in ethnic African obstetric patients who had delivered at the Aga Khan University Hospital, Nairobi, Kenya, by measuring levels of twenty-five hydroxyVitamin D (25OHD - the status marker of Vitamin D), noting that levels in pregnancy worldwide vary from 18 - 84%, and local levels are unknown. Methods: This was a cross-sectional prevalence study carried out at the Aga Khan University Hospital in Nairobi, Kenya, with the study population being ethnic African females who had delivered at the facility. This site was chosen as it is an urban hospital found within the equatorial belt, where majority of the population is dark-skinned (higher melanin levels hamper Vitamin D production via skin, the primary method through which Vitamin D is produced in the body). Blood samples were collected from 97 sequentially sampled newly delivered women after informed consent, and the levels of 25OHD were measured. The prevalence of deficiency was thereafter calculated. The Vitamin D levels were also related to the patient’s Body Mass Index, and their categorical amount of sun exposure. Results: The prevalence of Vitamin D deficiency in the stated population was calculated to be 79.4% (95% CI 70.5 - 86.6%). No association was noted between the Vitamin D levels, and the Body Mass Indices of the participants, and neither was an associated relationship inferred between Vitamin D levels and the sun exposure times. Conclusion: It is concluded that the prevalence of Vitamin D deficiency is present in a significant proportion of the ethnic African urban mothers that choose to deliver at the Aga Khan University Hospital in Nairobi, Kenya. This figure is noted to be amongst the upper part of the range signifying Vitamin D deficiency in pregnancy the world over (18-84%). Recommendations: Further to this finding, the study provides evidence for routine Vitamin D supplementation during pregnancy in ethnic African females living in equatorial cities. Larger