Background: Idiopathic pulmonary fibrosis (IPF) was reported to be associated with an increased risk of lung cancer. However, there had been few studies whether IPF affect long term survival of lung cancer. The primary goal of this study is to evaluate the impact of IPF on lung cancer survival. In addition, variety of clinical characteristics of patients with lung cancer and IPF were investigated. Methods: 70 patients who had both IPF and histologically proven lung cancer were identified through a search of Seoul National University Bundang Hospital database for 2003 to 2012. Of them, surgically treated 33 cases were matched with 66 lung cancers without IPF. Matched variables included age, sex, cell type and stage of lung cancer. Results: Of 70 subjects, 94% were male and the median age was 70 years (range 46-90). 81% of the cancer was located in the periphery of the lung and 56% in the lower lobe. The majority of the cancers (70%) were found in the fibrotic area. The most frequent cell type was squamous cell carcinoma (40%), and which is a far different result from the total lung cancer of Korea (currently, the most frequent histopathologic type is an adenocarcinoma(36%)). In surgically treated patients (33:66), the 5-year survival rates were 38% in lung cancer patients with IPF and 73% in those without IPF (p=0.001). Conclusions: Regardless of age, gender, pathologic type, and/or stage, IPF reduced survival of patients with lung cancer in surgically treated patients. The features of the lung cancer in patients with IPF were different from the total lung cancer population.