Small bowel neoplasms are very uncommon, especially leiomyosarcoma of the small bowel. Therefore, there is often a delay before small bowel leiomyosarcoma is diagnosed and treatment is started. A 60-year-old Caucasian male was admitted to our hospital with progressive melena. Gastroscopy and colonoscopy did not reveal the cause of the melena, but magnetic resonance imaging showed a jejunal tumor. After laparoscopic resection, the tumor appeared to be a grade 2 leiomyosarcoma. Small bowel neoplasms can be accurately detected by magnetic resonance enterography or wireless capsule endoscopy. Treatment almost always consists of resection of the primary tumor and its metastases. The role of chemo- and radiotherapy is not yet clear and prognosis remains very poor, with low five-year survival rates.