Interstitial lung disease (ILD) covers many common and less common diseases of lung, often involving the pulmonary structure. There are known causes for the development of ILD such as allergic reactions, exposure to pollutants as well as genetic and rheumatological diseases. However, often the cause is unknown (idiopathic). In some cases, scarring of the lung tissue (fibrosis) may occur. However, areas of fibrosis may also form after surgical interventions or infections. The term may sometimes be misleading and an area of fibrosis should not be confused with idiopathicpulmonary fibrosis (IPF), which constitutes a disease in the spectrum of ILDs. The diagnosis is often made by means of computer tomography, specific laboratory tests,bronchoscopy with immuno-typingof inflammatory cells and lung function tests. The resultsare often discussed in the context at a special ILD-board in order to assess the correct diagnosis and to initiate the correct therapy. The ILD- board takes place every two weeks at the University Hospital of Vienna.