Many institutions have developed outpatient observation units as an alternative to short-stay inpatient admissions. In this article, we highlight evidence to support the efficacy of EDOU care for chest pain and identify areas in which additional research is needed. Evidence-based protocols and collaborative approaches to care have potential to achieve similar clinical and improved economic outcomes compared with hospital admission. The potential for the EDOU to provide the right care for the right patient at the right time is only beginning to be realized, with significant advances in health care delivery anticipated in the near future. © 2012 Elsevier Inc.