Background: Miscarriage is the most common negative outcome in pregnancy worldwide. Its identification of modifiable risk factors is playing an important role in public health. Low vitamin D concentrations in pregnancy are widespread worldwide and the effects of vitamin D deficiency in pregnancy have been associated with some adverse pregnancy outcomes. We have very limited research-oriented information regarding the correlation between serum vitamin D deficiency and early spontaneous pregnancy loss. Aim of the study: The aim of this study was to evaluate the association of maternal serum vitamin D deficiency with early spontaneous pregnancy loss. Methods & Materials: This case-control study was carried out in the Department of Obstetrics and Gynaecology, Sir Salimullah Medical College and Mitford Hospital, Dhaka, Bangladesh during the period from September 2018 to August 2019. A total of 100 patients, 50 pregnant women having early spontaneous pregnancy loss (documented by ultrasonography as missed or incomplete abortion) was considered as the case (Group I). Age, gestational age and BMI matched another 50 women in their early live pregnancy (documented by ultrasonography) was served as control (Group II) in this study. The biochemical parameter measured in this study included fasting serum 25-hydroxy vitamin D level. Serum 25(OH)D level<20 ng/ml was classified as vitamin D deficiency and <10 ng/ml was classified as vitamin D severe deficiency. Statistical analyses of the results were obtained by using window-based computer software devised with SPSS version 22.0. Results: In analyzing vitamin D level (ng/ml) of the participants of this study it was found that more than half (52.0%) patients had severe deficiency (<10 ng/ml) in group I and 14(28.0%) patients in group II. 24(48.0%) patients had deficiency (10-20 ng/ml) in group I and 35(70.0%) in group II. Only 1(2.0%) patient had insufficiency (21-29 ng/ml) in group II. None of the patients had sufficient serum vitamin D levels. In comparing the serum vitamin D level (ng/ml) between group I and group II it was observed that the mean vitamin D level was 9.98±2.56 ng/ml in group I and 11.51±2.96 ng/ml in group II. The difference was statistically significant (p<0.05) between the two groups. Conclusion: Serum Vitamin D was significantly low in women with early spontaneous pregnancy loss as compared to pregnant women with early live pregnancy. Serum Vitamin D was deficient predominantly in both cases and control. Maternal serum vitamin D deficiency was significantly associated with early spontaneous pregnancy loss.