A rare case of bladder cancer producing granulocyte colony-stimulating factor (G-CSF) is reported. A 63-year-old man with a progressive, grade 3 transitional cell bladder carcinoma, showed marked leukocytosis (maximum 181,800/mm3) and an elevated serum G-CSF to 131.7 pg/mL. After radical cystectomy and neoadjuvant chemotherapy, the tumor recurred locally. Immunohistochemical examination with monoclonal antibody specific for G-CSF revealed positive staining in the local recurrent tumor. To our knowledge, there have been only seven cases reported of bladder cancer producing G-CSF.