We report an extremely rare case of gastric metastasis from a granulocyte colony-stimulating factor (G-CSF)-producing carcinoma of the esophagus. A 63-year-old Japanese man presented with an aggressive esophageal and gastric tumor and concomitant severe leukocytosis (21,700/mm3) with pyrexia. The serum level of G-CSF was markedly elevated to 253 pg/ml (normal < 9.8 pg/ml). Histological examination of the surgical specimen showed a moderately differentiated squamous cell carcinoma (SCC) of the esophagus and stomach, with tumor cells immunohistochemically positive for G-CSF. The leukocyte count and G-CSF concentration decreased after surgery. The patient was diagnosed with G-CSF-producing esophageal SCC with gastric metastasis. This is the first case of G-CSF-producing esophageal SCC with gastric metastasis.