An 82-year-old woman, who underwent a mastectomy for right breast cancer 35 years ago, presented to our hospital with a chief complaint of general malaise and dyspnea. A chest CT scan revealed a right pleural effusion and multiple bone metastases. Upper gastrointestinal endoscopy revealed a small bulge in the mid gastric fold, which was diagnosed as a metastatic breast cancer lesion, based on pathological diagnosis and immunostaining findings. The patient had triple-negative breast cancer and was started on docetaxel therapy despite her advanced age. The pleural effusion disappeared, tumor marker levels normalized, and treatment was continued. Here, we report a case of late recurrence of breast cancer with gastric metastasis 35 years postoperatively.