Diffuse parenchymal lung diseases (DPLDs) are a heterogeneous group of diseases characterized by damage to the lung parenchyma arising from the effects of inflammation and fibrosis. While the interstitium is the primary site of injury, the airspaces, peripheral airways and vessels are also commonly involved. This group of disorders was popularly referred to as interstitial lung diseases (ILDs) till the International Consensus Statement was formed by the American Thoracic Society (ATS) and the European Respiratory Society (ERS). New insight into the pathogenesis and diagnostic techniques, like high resolution CT scanning, made significant contributions to a better understanding of these diseases. The DPLDs comprise about 200 entities of known and unknown causes. Management of DPLDs is always a challenge, but early diagnosis, appropriate treatment and a balanced prognostic evaluation are always rewarding.