The prognosis of granulocyte colony-stimulating factor( G-CSF) -producing lung cancer is very poor. We present a case of G-CSF-producing locally advanced non-small cell lung cancer successfully treated with chemoradiotherapy. A 65-year-old man presented with a slight fever, general fatigue, and cough. A mass was detected in the right upper lobe of his lung, and it was diagnosed as squamous cell carcinoma by computed tomography (CT) -guided needle biopsy. Laboratory data indicated marked leukocytosis and elevated serum G-CSF levels, and therefore, the tumor was strongly suspected to be G-CSF-producing lung cancer. After systemic evaluation, the patient was treated with concurrent chemoradiotherapy for cT3N2M0, stage IIIA non-small cell lung cancer. Complete response (CR) was achieved, and he remained well with no recurrence of the cancer for over 3 years after treatment. Although immunohistochemical staining results for G- CSF were negative, clinically, the tumor was diagnosed as G-CSF-producing lung cancer.