Primary squamous cell carcinoma (SCC) of the stomach is a very rare disease. However, the pathogenesis, clinical characteristics, and prognosis of gastric SCC are controversial and remain to be elucidated. Herein, we report a case of primary gastric SCC of the remnant stomach after subtotal gastrectomy. A 65-year-old man was admitted to our hospital due to epigastric discomfort and dizziness. He had undergone subtotal gastrectomy 40 years previously for gastric ulcer perforation. Endoscopy revealed a normal esophagus and a large mass in the remnant stomach. Abdominal computed tomography revealed enhanced wall thickening of the anastomotic site and suspected metachronous gastric cancer. Endoscopic biopsy revealed SCC. Total gastrectomy was performed with Roux-en-Y esophagojejunostomy. A 10-cm tumor was located at the remnant stomach just proximal to the previous area of anastomosis. Pathologic examination showed well-differentiated SCC extended into the subserosa without lymph node involvement (T3N0M0). The patient received adjuvant systemic chemotherapy with 6 cycles of 5-FU and cisplatin regimen, and he is still alive at the 54-month follow-up. According to the treatment principles of gastric cancer, early detection and radical surgical resection can improve the prognosis.