The purpose of this communication is to report six cases of carcinoma of the suprapapillary segment of the duodenum and to analyze and summarize the data obtained from the reported cases of this condition. Reports of one hundred and four cases were abstracted from the literature, thirty-five1 of which were regarded as acceptable on the basis of the data presented, a clinical history and gross and microscopic studies of the primary lesion being presented in each report. Twelve2 additional cases, although probably authentic examples of this condition, could not be included in the present analysis because of insufficient clinical or pathologic data. Fifty-seven more reported cases were discarded, nineteen because, owing to involvement of the stomach, pancreas or bile passages in the malignant process,3 the duodenal origin of the lesion was not established with certainty and thirty-eight4 because the histologic studies were not reported, the diagnosis