A seventy-seven-year-old man was found to have a duodenal tumor by X-ray examination, which was identified to be malignant one by an endoscopic examination. On admission a slight anemia, increased erythrocyte sedimentation rate, positive occult blood reaction in stool were desclosed. An upper G.I. series revealed a filling defect of duodenal bulb. A duodenal endoscopic examination showed a protruding lesion on the greater curvature of the front wall of duodenal bulb. A biopsy specimen obtained at the same time was identified as a well differentiated adenocarcinoma tubulare by histological study. Local injection of MMC, 5Fu and predonin under endoscopic observation was performed weekly four times. Nevertheless the lesion have remained stationally. The patient have been well and still remaines under our medical supervision.