Multiple primary cancers including small intestinal tumors are rare. We describe the first curative resection case of metachronous triple early cancers involving the jejunum as well as the stomach and esophagus. The patient had undergone total gastrectomy for a gastric adenocarcinoma and subsequent esophagectomy for an esophageal squamous cell carcinoma. A jejunal adenocarcinoma, the third primary, occurred at the blind stump of the jejunal limb of a Roux-en-Y esophagojejunostomy reconstructed previously. This tumor was removed by partial resection of the limb with the preservation of the esophagojejunostomy. The patient died from complications of acute pancreatitis 3 years after the last operation, without overt clinical signs of cancer recurrence. Immunohistochemistry of the specimen showed the increased expression of p53 and cyclin D1 proteins in all three cancers, suggesting their involvement in metachronous carcinogenesis in this case. Early diagnosis of each cancer was made possible by regular endoscopic follow-up and favorable anatomical location of each tumor, which were considered to allow less invasive surgery as well as to contribute to the favorable outcome. This case suggests the importance of regular surveillance for metachronous carcinogenesis, especially when the preceding cancers carry genetic abnormalities that may potentially increase the risk for subsequent carcinogenesis.