The term interstitial lung disease (ILD) encompasses a large variety of entities. The clinical diagnosis is often difficult and is a multidisciplinary process. Achieving the correct diagnosis often involves 3 elements: a clinical impression, radiologic evaluation, and a pathologic opinion. All 3 components play a critical role. Frequently, the goal is differentiating idiopathic pulmonary fibrosis (IPF) from more treatable entities. This article provides an overview of the input provided by the 3 specialties cited earlier, as well as the interrelationship among these specialties in the diagnosis of ILD. Additional consideration is given to the decision-making process involved in determining when to obtain a biopsy specimen from a patient with ILD, and a review of current treatment strategies.