Patients with gallbladder carcinoma rarely have remarkable granulocytosis. Although surgical resection is the most effective treatment, patients with gallbladder carcinoma generally have a very poor prognosis. We report a case of a rapidly growing gallbladder tumor associated with remarkable granulocytosis in a patient who has survived without recurrence for more than 2 years since undergoing resection. The patient had remarkable leukocytosis of 51,500/mm(3) with 89% granulocytes and an elevated granulocyte-colony stimulating factor (G-CSF) level of 800 pg/dl. We performed cholecystectomy with extended right lobectomy of the liver and lymph node dissection. A histological diagnosis of moderately differentiated gallbladder carcinoma with sarcomatous change invading the hepatic parenchyma was confirmed. An immunohistochemical examination using polyclonal antibody against G-CSF was performed to stain the tumor cells, which confirmed the diagnosis of a G-CSF-producing tumor.