Adenosine is an endogenous nucleoside that has been shown to be beneficial for the myocardium in different settings by a large number of experimental studies. In this article, we 1) outline adenosine's metabolic pathways, 2) address cardioprotective properties of adenosine, and 3) discuss possible implications of the two recently published clinical studies disclosing a positive effect of adenosine monophosphate deaminase 1 (AMPD1) gene mutation on cardiovascular survival in heart failure and ischemic heart disease. (Fig. 2, Ref. 84.)