BackgroundFusobacterium nucleatumis a common oral symbiotic flora that can cause respiratory tract, oral nervous system, obstetric and skin infections.Fusobacterium nucleatuminfections are mostly caused by aspiration. The clinical manifestations of pulmonary infections withFusobacterium nucleatumcan include simple pneumonia, lung abscesses, empyema, etc.Case presentationWe described the case of a 49-year-old man with a 1-year history of intermittent cough and sputum production who had worsened over the last 4 days with fever and right chest pain. After thoracentesis and catheter drainage were performed,Fusobacterium nucleatumwas detected in the pleural effusion by using next-generation sequencing. Meanwhile, a diagnosis of squamous cell carcinoma of the right lung was made by fiberoptic bronchoscopy. The patient's condition improved significantly after percutaneous drainage and long-term intravenous antibiotic treatment.ConclusionsThis is the first case reported of empyema due toFusobacterium nucleatuminfection in a patient with squamous cell carcinoma.