A 77-year-old woman visited our institution complaining of general fatigue. Chest radiography revealed masses in the upper and middle lung fields. Pathological findings for an endoscopic biopsy specimen revealed squamous cell carcinoma. High-grade fever developed and blood analyses revealed sustained elevated white blood cell count and C-reactive protein levels. Cytokine production by tumor cells was suspected; both serum granulocyte colony-stimulating factor (117 pg/mL; normal: <57.5 pg/mL) and interleukin-6 (83.5 pg/mL; normal: <2.41 pg/mL) levels were high. Immunohistochemical examination of biopsy specimens showed positive staining with antigranulocyte colony-stimulating factor and anti-interleukin-6 monoclonal antibodies. Diagnosis of a tumor that produced granulocyte colony-stimulating factor and interleukin-6 was established. The patient was administered best supportive therapy since she was not eligible for surgical treatment because of her poor respiratory function. She died from interstitial pneumonia exacerbation two months after this diagnosis. We present a female with squamous cell carcinoma of the lung that produced granulocyte colony-stimulating factor and interleukin-6.