Purpose: Clostridium difficile infection (CDI) is a common nosocomial infection. Because of continuous antibiotic treatment or chemotherapy, prolonged hospitalization, and general weakness, lung cancer patients are at a high risk of developing CDI. The aim of this study was to evaluate whether the clinical and laboratory factors associated with lung cancer are correlated with CDI and to evaluate the clinical features of CDI. Methods: The study was designed as a retrospective review of lung cancer patients admitted to the Wonkwang Medical Hospital from 2008 to 2010. Results: This study included 232 patients with lung cancer, of whom 44 were diagnosed with CDI. The albumin levels were significantly lower in the CDI (+) lung cancer patients than in the CDI (-) lung cancer patients (p＜0.05). Further, the performance status (PS) score of the CDI (+) lung cancer patients was significantly higher than that of CDI (-) lung cancer patients (p＜0.05). Conclusions: CDI should always be suspected, especially in patients with low albumin levels and high PS scores because most of the lung cancer patients are at a risk of developing CDI.