Introduction: Superior mesenteric artery (SMA) usually arises from the abdominal aorta, just below the celiac trunk and it supplies the midgut-derived embryonic structures. Anatomical variations in this vessel contribute to problems in the formation and/or absorption of this part of the intestine and its absence has been recognized as the cause of congenital duodenojejunal atresia. Objective: To analyze SMA anatomical variations in humans and the possible associated clinical and surgical implications. Methods: This is a systematic review of papers indexed in PubMed, SciELO, Springerlink, Science Direct, Lilacs, and Latindex databases. The search was performed by two independent reviewers between September and December 2018. Original studies involving SMA variations in humans were included. SMA presence/absence, level, place of origin and its terminal branches were considered. Results: At the end of the search, 18 studies were selected, characterized as for the sample, method to evaluate the anatomical structure and main results. The most common type of variation was when SMA originated from the right hepatic artery (6.13%). Two studies (11.11%) evidenced the inferior mesenteric artery originating from the SMA, whereas other two (11.11%) found the SMA sharing the same origin of the celiac trunk. Conclusion: SMA variations are not uncommon findings and their reports evidenced through the scientific literature demonstrate a great role for the development of important clinical conditions, making knowledge about this subject relevant to surgeons and professionals working in this area.