As the diagnostic assessment of the different forms of interstitial lung disease (ILD) is similar, this study aims to compare age, sex, the functional and broncho-alveolar lavage fluid (BALF) findings at diagnosis between the different forms of ILDs. In addition we want to determine which of these variables determine survival. We evaluated 315 patients (176 males and 139 females) in whom the diagnosis was made of sarcoidosis (n = 87), ILD due to connective tissue disease (n = 56), hypersensitivity pneumonitis (n = 50), idiopathic pulmonary fibrosis (IPF) (n = 64), other forms of idiopathic interstitial pneumonia (n = 29) or ILD due to an undefined form of fibrosis (n = 29). We analysed the role on outcome of type of disease, gender, age at diagnosis, type of cells in BALF, FVC and DLCO. In a Kaplan-Meier analysis IPF has the worst outcome in comparison with other types of ILDs. A Cox regression analysis showed that type of ILD, FVC, age at diagnosis and % of macrophages in BALF predict outcome of patients affected by ILD.