Myocardial perfusion imaging is a well-established noninvasive modality for the diagnosis and prognosis of coronary artery disease. The pharmacologic stress agents adenosine and dipyridamole are widely used in imaging studies, but cause undesirable side effects, like atrioventricular block and bronchospasm, due to their nonselective adenosine receptor activation. Furthermore, the mode of administration of these agents as a bolus infusion is less preferred. Regadenoson, an A2A adenosine receptor selective pharmacologic stress agent was approved in 2008 and is widely used instead of adenosine and dipyridamole. This article reviews regadenosons structure, mechanism of action, advantages over adenosine and dipyridamole, and its role in various patient populations undergoing stress perfusion imaging. Emerging applications where regadenoson could be of potential use are also explored.