Many, different diseases can result in pulmonary fibrosis and its prevalence is continuously increasing. Pulmonary fibrosis is defined by a diffuse accumulation of connective tissue in the interstitial space resulting in destruction of lung parenchyma. Older individuals are more often affected by this disease than younger. Approximately one half of all patients with pulmonary fibrosis suffer from rheumatic diseases. The classification of pulmonary fibrosis was revised 1998. Now 6 different types of interstitial pneumonia according to 6 different pathologic patterns are newly defined. Still, there is no efficient treatment known, which resolves fibrotic lung remodeling. However, immunosuppressive treatment strategies are established in pulmonary fibrosis evoked by inflammatory processes.