Only a few cases of de novo malignancy, especially gastric cancer after living donor liver transplantation (LDLT), have been reported. We report a case of gastric cancer following LDLT, after which immunosuppressants were minimized in accordance with the results of the mixed lymphocyte reaction (MLR) assay. A 65-year-old woman had previously undergone LDLT for hepatocellular carcinoma associated with hepatitis B virus infection. The liver graft had been donated by her son. During the course of postoperative surveillance with the MLR assay in order to minimize immunosuppressants, she was incidentally found to have gastric cancer during an endoscopic examination, 8 years after the liver transplantation. She underwent total gastrectomy with lymph node dissection. In this case, gastric cancer was detected 8 years after LDLT, which is longer than previously reported intervals between LDLT and malignancy detection. The number of patients undergoing LDLT is increasing, and the prognosis after liver transplantation has improved. Therefore, endoscopic surveillance programs are important for detecting malignancies in the early stages in liver transplant recipients.