Invasion of the duodenum by contiguous cancer or an isolated metastasis can manifest itself with the signs and symptoms of primary cancer of the duodenum. Fourteen patients were identified with this type of diagnostic confusion. All of their tumors were in the 2nd or 3rd portion of the duodenum. Although the median length of survival after excision of the tumor or palliative bypass operations in these patients was 9 mo., considerably longer survival times were also described. Ba enema examinations and excretory urograms should be considered as diagnostic tests for any patient with a tumor of the duodenum to identify the contiguous carcinomas of the colon and kidney subject to long palliation.