Background: A low level of vitamin D is strongly correlated with a decreased calcium level, which in turn leads to inadequate mineralization of bones with subsequent development of rickets in children or osteoporosis in adults. It results not only in bone deformation, but also in high susceptibility of falls and bone fractures. Thus, proper vitamin D supplementation according to recent standards is essential for maintenance of the body homeostasis. The aim of the present study was to clinically assess the effect of empirical vitamin D supplementation on unexplained recurrent early pregnancy loss. Methods: This study was a prospective study (Clinical trial study) which included 80 women suffered from unexplained RPL. They were selected carefully from outpatient clinic in Banha University Hospitals. Results: Parity showed a significant difference between both groups; it ranged from 0-2 in group A and from 0-3 in group B. No significant differences were noted between both groups regarding age. No CMV, toxoplasmosis, or rubella infections were reported in both groups. HCT was significantly higher in group A (37.3 %) compared to group B (36.3%). No positive APA was detected in both groups. Abortion showed non-significant difference between both groups. Conclusion: Vitamin D minimize the incidence of abortion among women with unexplained recurrent early pregnancy loss, but this decrease was not significant. The effects of vitamin D on the immune regulation of RPL indicate that vitamin D might be used as an alternative therapy in the future.