BACKGROUND AND OBJECTIVE: There are several studies related to the role of the hematologic agents in the etiology of recurrent aphthous stomatitis (RAS) which results have controversies. This study was carried out to investigate the etiologic role of iron, folic acid and vitamin B12 in RAS. METHODS: In this systematic review and meta analysis study, databases were searched with specific keywords in mentioned period of time after determining research question. At the end, 24 articles were identified and included in this study. All studies were critically appraised. Data were extracted and stratified and meta-analysis was done for all extracted data. FINDINGS: Meta analysis showed that prevalence of low level of hematinic agents (ferritin, serum iron, hemoglobin, serum folate, RBC folate and vitamin B12) in patients with RAS was significant (p<0.1). In interventional studies, healing of RAS after prescription of iron supplement was significant (p<0.1) CONCLUSION: Based on the gained results, hematologic deficiencies of ferritin, serum iron, hemoglobin, serum folate, RBC folate and vitamin B12 have a notable role in the etiology and recurrence of aphthous ulcers and ordering iron supplements for RAS patients is beneficial.