Aim: To compare vitamin D levels in the serum of women in the first three months of gestation with bacterial vaginosis (BV) occurrence in a tertiary care hospital. Materials and methods: Bacterial vaginosis diagnosis was done using the Nugent scoring system. It has been considered as one of the best standards to diagnose BV. Vitamin D analysis was done using ELISA method. Results: About 66.7% of pregnant women positive for BV in the first trimester of pregnancy were with vitamin D deficiency, 22% of women who had a normal vaginal flora had sufficient measures of vitamin D in the serum. In this study, the subnormal and deficient measures of vitamin D had a good and significant association in women with BV with a p-value of 0.007. Conclusion: In women in the first trimester of pregnancy, BV has significant association with deficient measures of vitamin D in the serum. Clinical significance: Bacterial vaginosis presenting as vaginal discharge is mainly caused by increase in the levels of anaerobic bacteria. There is a balance between Lactobacillus species, which is present in abundance and maintains the normal pH of the vaginal fluid with anaerobic bacteria, which is altered in BV. It is said to be a polymicrobial clinical syndrome that can lead to preterm birth and its related complications. In developing countries, public health diseases are given importance and one among them is vitamin D deficiency. Interestingly, deficient measures of vitamin D have been found to be increasingly linked to the symptomatic presentation of several medical and immunological conditions that can lead to hypertension, diabetes in pregnancy, and can also lead to preterm labor. In this study, we tried to see if there is any relationship between BV and deficiency of the levels of serum vitamin D in the first trimester of pregnancy. Diagnosing BV and vitamin D deficiency in the first trimester gives us ample opportunity to treat and reduce the obstetric complications.