Interstitial lung disease (ILD) is a huge group of lung disorders and these days it is getting more common than previously diagnosed. It can be categorized into three main classes: autoimmune disease associated ILD, drug induced ILD, and idiopathic ILD. For rheumatoid arthritis associated ILD, interstitial pneumonia is one of the most common complications, and three drugs (prednisone, mycophenolate mofetil, and cyclophosphamide) are used. Among idiopathic ILD, number of new cases and mortality for idiopathic pulmonary fibrosis (IPF) are rising. With the old treatment, three-drug regimen (azathioprine, prednisone, and N-acetylcysteine), rate of death and hospitalization were increased. Nowadays, with increasing recognition of fibroblast proliferation in the pathogenesis of IPF, treatment is turning towards antifibrotic agents, which are pirfenidone and nintedanib.