A case of mesenteric fibrosis secondary to post-traumatic mesenteric hematoma, resulting in duodenal stenosis eight years after the traumatic event is presented. A 50 year-old man was hospitalized with nausea and vomiting. An intraabdominal cystic mass was seen in abdominal ultrasonography and CT. Duodenum was found to be obstructed due to extrinsic compression in upper endoscopy. At laparotomy there was an intramesenteric traumatic cyst and fibrosis around the duodenum resulting in duodenal obstruction. After the cyst was unroofed a Roux-en-Y duodenojejunostomy was performed. Both early and late (after 4 months) follow-up results were excellent.