Lansoprazole is an acid proton-pump inhibiting drug that is used for the treatment of duodenal or gastric ulcers, H. pylori infection, gastroesophageal reflux disease or Zollinger-Ellison syndrome. Although lansoprazole is well known for its gastrointestinal and dermatologic adverse effects, mild pulmonary symptoms are also known to develop from taking this drug. There have been no reports about lansoprazole-induced interstitial lung disease. We report here a case of lansoprazole-induced interstitial lung disease that developed in a 66-year-old man.