Undifferentiated cancer of the small intestine has a poor prognosis and has rarely been reported.We report a case of undifferentiated intestinal carcinoma.A 55-year-old man presented with epigastralgia in December 2018. Blood test results showed a high degree of anemia.Contrast -enhanced abdominal CT showed a small intestinal tumor with a diffuse thickened wall along with multiple liver metastases.Capsule endoscopy revealed a bleeding tumor.It was diagnosed as carcinoma by transhepatic-ultrasound-guided core needle biopsy.Given the preoperative diagnosis of intestinal carcinoma, we resected the tumor along with a part of the small intestine and the enlarged lymph nodes.The pathological diagnosis was undifferentiated intestinal carcinoma.The patient was discharged on the 6th postoperative day after surgery.He was scheduled to receive postoperative chemotherapy.There was no evidence of undifferentiated intestinal carcinoma.Herein, we review case reports from the literature.