PURPOSES: Acute exacerbation of interstitial pneumonia (AEIP) is a leading cause of death after lung cancer resection in patients with interstitial lung disease. METHODS: We retrospectively analyzed 1763 patients with non-small cell lung cancer with a clinical diagnosis of interstitial lung disease (ILD) who underwent lung cancer resection between 2000 and 2009 at 61 hospitals in Japan. AEIP occurred in 164 of 1763 (9.3%) patients with a mortality rate of 43.9% (72/164). Univariate and multivariate analyses were carried out to identify possible risk factors of fatal AEIP. We then analyzed the 164 patients who developed postoperative AEIP and identified the preoperative and postoperative risk factors. RESULTS: A multivariate regression analysis identified that the sex, percent vital capacity, neoadjuvant radiation, preoperative history of AEIP, preoperative use of steroids, usual interstitial pneumonia pattern on CT, and surgical procedures were independent preoperative risk factors for death due to AEIP. ILD patients with emphysema somehow showed a lower risk of fatal AEIP than those without emphysema in this study. CONCLUSIONS: This study revealed eight risk factors for fatal AEIP.