Adult-onset Still's disease (AOSD) has been recognized as a cause of fevers of unknown origin. Malignancies are the most important differential diagnoses of AOSD which has been rarely reported in association with cancer. The present paper undertakes the study of a 69-year-old Tunisian woman with AOSD according to the diagnostic criteria of Yamaguchi. She was treated by prednisone, then associated with methotrexate. 18 months later, she developed a squamous cell carcinoma treated with chemotherapy and radiotherapy.