Interstitial lung diseases (ILD) are a heterogeneous group of parenchymal lung disorders eventually resulting in respiratory failure that can be classified into those with known and unknown causes. ILD are characterized by deposition of cellular and non-cellular components into the lung parenchyma but vary widely in etiology, clinico-radiologic presentation, histiopathologic features, and clinical course. A combination of clinical context, medical and environmental history, physiologic testing, lung imaging, serologic testing and histiologic findings obtained through bronchoscopic or surgical lung biopsy provides the basis for a precise diagnosis. In particular, high-resolution computed tomography of the chest and recognition of the prognostic importance of separating usual interstitial pneumonia (UIP) from other idiopathic interstitial pneumonias (IIP) have profoundly changed the management of patients with ILD. Besides, smoking cessation, avoidance of antigen or inorganic dust exposure, corticosteroids alone or in combination with azathioprine and cyclophosphamide are still the mainstay of therapy for most entities. However, the poor response rates to immunosuppressive therapy for UIP patients and frequent adverse effects highlight the need for new therapeutic strategies confirmed by randomized clinical trials to guide treatment. So far, lung transplantation remains the treatment of last resort for eligible patients with progressive lung fibrosis and timely referral for transplant evaluation is mandatory owing to limited donor availability.