Paraduodenal hernia is a rare congenital anomaly that arises from an error of rotation of the midgut. The duodenum and the small intestine become trapped in a sac which is lined by the peritoneum, behind the mesentery of the colon, either to the right or left of the midline. It is therfore a rare and potentially life-threatening condition that can cause intestinal obstruction progressing to strangulation and perforation. We report a case of a 55-year-old patient presenting a left paraduodenal hernia diagnosed intraoperatively after being operated on in the emergency setting for acute abdomen. The small bowel was twisted upon its mesentery and was entrapped in a large left paraduodenal space. Fortunately, once the bowel was reduced from the paraduodenal space, the blood flow was reestablished and the small bowel resumed a proper functioning. The mouth of the sac was obliterated by suture opposition to the posterior wall. The patient's subsequent hospital course was uneventful, and he was discharged in satisfactory condition 4 days postoperatively.