A case of bladder squamous cell cancer producing granulocyte colony-stimulating factor (G-CSF) is reported. A 55-year-old female presented with macroscopic hematuria and urinary frequency. Cystoscopy demonstrated a large bladder tumor. Computerized tomography and magnetic resonance imaging of abdomen and pelvis showed bladder muscular invasion, but did not reveal any metastasis. Laboratory examination showed leukocytosis of 23,600/mm3 and a high value of granulocyte colony-stimulating factor (G-CSF) 77 pg/ml in the peripheral blood. She was diagnosed with bladder tumor 52 months ago, but did not seek further medical attention. The leukocyte count at that point was 10,700/mm3. Radical cystectomy was performed. The histopathological diagnosis was well differentiated squamous cell carcinoma. Immunohistochemical examination was positive for G-CSF. After surgery the leukocyte count and value of G-CSF in the peripheral blood decreased to the normal range. There has been no recurrence of cancer for 10 months after surgery without any adjuvant therapy.