Objective: Small bowel adenocarcinoma (SBA) is a rare disease but its clinical fea-tures have been clearly elucidated. The present study clarified the clinicopathological characteris-tics, the effectiveness of the surgical procedure, neoadjuvant chemotherapy, and adjuvant chemo-therapy of the patients with SBA. Patients and Methods: The clinicopathological characteristics of 9 cases of SBA resected at our hospital were reviewed between 2004 and 2017. Results: The mean age of the 9 patients (4 men, 5 women) was 69.6 (57-83) years. The sites in-cluded the duodenum (n=3), jejunum (n=3), and ileum (n=3). As neoadjuvant chemotherapy, S-1 was administered to a patient with a large duodenal adenocarcinoma invading the portal vein. The surgical procedures included partial resection of jejunum (n=3); partial resection of ileum (n=3); py-lorus-preserved pancreatoduodenectomy (PD) (PPPD) with right hemicolectomy due to invasion of ascending colon (n=1); subtotal stomach-preserving PD (SSPPD) (n=1); and wedge resection of the duodenum (n=1). The stage was classified as follows: stage I (n=1), stage IIA (n=1), stage IIB (n=3), stage IIIA (n=1), stage IIIB (n=2), and unknown, (n=1). As adjuvant chemotherapy, S-1 was adminis-tered to three stage IIB patients, one IIIA patient, and one IIIB patient. Tegafur uracil (UFT) + calcium folinate (LV) was administered to one stage IIIB patient. The cumulative five-year survival rate was 77.8%. Conclusions: Aggressive esophagogastroduodenoscopy, double-balloon endoscopy, and colo-noscopy for symptoms such as anemia and abdominal pain, as well as intraoperative during abdom-inal surgery, would improve the prognosis of SBA.