Background: Folate is a naturally occurring B vitamin, is needed in the brain for the synthesis of norepinephrine, serotonin, and dopamine. Thus, previous researches suggested that folate levels play an important role in the etiology and course of depression. However, the literature has been inconsistent regarding differences in folate level between individuals with and without depression. The present meta-analysis synthesized the results of previous studies to examine whether individuals with depression had lower levels of folate than individuals without depression. Aim of the Study: to assess the relationship between Depression and Folate deficiency. Methods: A review of the scientific literature (PubMed Search 1994 to 2017) Pubmed, Embase and CENTRAL were searched to identify randomized controlled trials that investigated The Correlation between Depression and Folate Deficiency as the primary outcome. Identification of papers and data extraction was performed by two independent researchers. We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to October 2017. Results: 8 studies were included enrolling 173000 participants; 1813 patients with depression and 15487 control subjects. Pooling of all estimates showed a significant correlation between folate status and depression (OR pooled unadjusted = 1.41; 95% CI 1.19 to 1.82), (OR pooled adjusted = 1.39; 95% CI 1.04 to 1.76). Conclusion: Low folate and B12 serum levels seem to be associated with depression Folate has been linked to depression and there is a strong body of evidence suggesting the introduction of folate supplement in the prevention and treatment of depression at the population and individual levels.