Sarcoidosis is a systemic granulomatous disease of unknown etiology that primarily affects the lungs. The etiology remains unclear; however, environmental, genetic, ethnic, and familial factors probably modify expression of the disease. As an example, African Americans are at greater risk of mortality and morbidity than are white Americans, and more often have a family history of sarcoidosis. Most patients with sarcoidosis recover spontaneously, but some develop chronic, debilitating disease. Corticosteroids and other drugs, although effective at controlling disease activity, may not influence the overall course of disease. Because of the many uncertainties about the pathogenesis, course, and management of sarcoidosis, the National Heart, Lung, and Blood Institute convened a working group to identify future research directions and opportunities for sarcoidosis. These include developing a tissue bank, using novel methods to identify genetic factors, studying the immunopathogenesis with human tissue and animal models, exploring new approaches to diagnose and manage disease, and, finally, conducting randomized controlled trials to assess new therapies.