Gastrointestinal cancer is common, and is a significant cause of morbidity and mortality. The synchronous occurrence of two different malignancies is not uncommon, but that of more than two malignancies is extremely rare. Such occurrences often pose diagnostic and therapeutic challenges. We report the case of an elderly man who was previously treated for gastric cancer 13 years ago, and who was later diagnosed with synchronous triple gastrointestinal malignancies consisting of hepatocellular carcinoma, a gastric collision tumour with adenocarcinoma and a large B cell lymphoma. The patient's condition progressed rapidly, and he died four weeks after the diagnosis.