Interstitial lung diseases are a broad, diverse, challenging group of diseases, most of them chronic whose prognosis is not good. In the last two decades there have been considerable advances in the knowledge of the epidemiology, pathological and genetic bases and treatment of several of these diseases. This article summarizes and presents updated information about their classification, new knowledge on genetics and treatments in idiopathic pulmonary fibrosis, advances in the diagnosis and management of hypersensitivity pneumonitis and a review of the broad spectrum of interstitial diseases associated with connective tissue diseases. Several clinical trials are currently underway whose results will be available in the coming years and will provide more information and tools to improve the treatment of these patients.