Spontaneous small bowel mesentery or retroperitoneal hematomas are rare pathology occurring in absence of any trauma, anticoagulant therapy, vessel’s anomaly or systemic inflammatory disease. We present a case of a 23-year old male patient diagnosed with small bowel mesentery hematoma that corresponds to the „spontaneous” definition, who was admitted three days after onset accusing pain and a tumorous mass in the mesogastric region. Abdominal US and CT revealed a high density tumorous mass with well defined borders and nonhomogenous content, localized anterior to the left kidney, being in intimate contact with the small bowel loops and the transverse colon. Surgery was performed and the mesenteric hematoma was completely removed. Histological examination revealed characteristic changes for encapsulated hematoma. Postoperative period was uneventful, the patient being disease free during 24 months followup.