Background: Vitamin D (vit D) regulates the female reproductive system and inflammation reduction. Vit D deficiency has been reported to be related to various diseases, such as infertility in females. Objective: This work aimed to study the effect of vitamin D deficiency and vaginal inflammation on the pregnancy rate following frozen embryo transfer. Subjects and Methods: This prospective study included 188 infertile females who underwent ICSI protocol between ‎‎ February ‎2021‎ and January ‎2022. The individuals were categorized into two groups: Group I (Vit D deficiency, vit D < 30 ng/‎mL), and group II (Normal vit D ≥ 30 ng/‎mL)‎. Vitamin D‎ levels in serum and vaginal inflammation were detected, and pregnancy outcomes were compared between the groups. The impact of vitamin D deficiency and vaginal inflammation on the pregnancy ‎rates was ‎investigated.‎ Results: ‎Among participants, 74.3% had vitamin D deficiency‎, and 25.5% had normal vit D levels. ‎‎37.23% of patients had a positive β-hCG, while 62.77% had negative β-hCG. 14.9% of ‎cases had no vaginal infection, while 85.1% had a vaginal infection. There was a statistically ‎significant correlation between lower pregnancy rates in Egyptian females and vit D ‎deficiency ‎ (p < 0.001). However, there was no correlation association between vaginal ‎inflammation and pregnancy rates (p > 0.05). Logistic regression analysis showed that ‎reduced pregnancy outcome could be due to ‎ vit D (P<0.001‎).‎ Conclusion: Lower pregnancy rates following ICSI among Egyptian women ‎may be‎ related to vitamin D ‎deficiency, while vaginal inflammation has no impact on pregnancy rates.