Objectives: This study aimed on analyzing vitamin D serum levels and its impact on oocyte quality in patients undergoing in vitro fertilization (IVF) procedures at a human reproduction laboratory located in Curitiba, Brazil. Methods: This article is an observational cross-sectional study of retrospective data collected from the medical history of patients that have undergone IVF treatment between January 2015 and December 2015 in a specialized clinic (Clínica de Reprodução Dr. Ricardo Beck da Maternidade Curitiba) located in Curitiba, Brazil. Different vitamin D levels where compared with a variety of oocyte qualities and in vitro cleavage percentage. Results: We identified a prevalence of deficient (≤ 20 ng/mL) and insufficient (21-29 ng/mL) vitamin D levels among the patients in this study. No evidence was found that could confirm an effect of vitamin D on oocyte quality or in vitro cleavage percentage. Conclusion: Age has been shown to be an important factor in altering the number of oocytes available after pharmacological induction and oocytes with adequate quality for implantation at the end of the in vitro cycle. Due to the importance of the subject, further studies are essential for a better understanding of the effect of vitamin D on human fertility and IVF procedures.