Inclusion Criteria:  Adults ≥ 18 years at Visit 1 Subjects must be contractually capable and mentally able to understand and follow the instructions of the study personnel Physician's diagnosis of chronic fibrosing Interstitial lung disease (ILD) with a progressive phenotype, except Idiopathic pulmonary fibrosis (IPF) Treatment with nintedanib in this Non-interventional study (NIS) will be the first and only prescription of any antifibrotic treatment for each individual patient within this observational study after a physician's decision being made for this treatment option earlier Outpatients not currently hospitalized with a life expectancy > 12 months per investigator's assessment Written informed consent prior to study participation Current Forced vital capacity (FVC) measurement (taken within the last 3 months) available in the patient file Women of childbearing potential must take appropriate precautions against getting pregnant during the intake of nintedanib.  Exclusion Criteria:  Patients with contraindications according to Summary of product characteristics (SmPC) Prior use of any antifibrotic treatment Lack of informed consent Pregnant or lactating females Any physician diagnosed exacerbation of Interstitial lung disease (ILD) in the patient's history file, irrespective of time since event Current diagnosis of lung cancer Respiratory failure (pH < 7,35 and/ or respiratory rate > 30/min) in the patient's history Participation in a parallel interventional clinical trial Patients being spouse or lateral relatives to the second degree or economically dependent from the investigator