Clostridium difficile infection (CDI) is a common nosocomial infection. Lung cancer patients have a high risk of developing CDI because of continuous antibiotic treatment or chemotherapy, prolonged hospitalization, and general weakness. This study aimed to analyze predisposing or associated risk factors for CDI in lung cancer patients receiving chemotherapy. This study was a retrospective review of 188 lung cancer patients who were admitted to the Wonkwang University Hospital between 2008 and 2009. Of the 188 patients, 44 were diagnosed with CDI. The albumin levels were significantly lower and the performance status (PS) score was significantly higher in lung cancer patients with CDI than in those without CDI (P < 0.05). In conclusion, clinicians should consider the possibility of CDI occurrence in lung cancer patients receiving chemotherapy, particularly in those with low albumin levels and high PS scores, because most lung cancer patients have a high risk of developing CDI.