Eighteen cases of primary tumors of the duodenum were reported. There were four cases of benign tumors, and fourteen cases of malignancy. The tumor was located in the bulb of the duodenum in seven cases, the descending part in nine cases and the transversepart in two cases. Five cases were complicated with intestinal perforation. Four cases with hemorrhage, four cases with obstruction and five cases with choledochal obstruction. The pathology, diagnosis and treatment of primary duodenum tumors are discussed.