Heart disease is a major cause of morbidity and mortality in the developed world. Patient recovery after cardiac injury is hampered by the extremely limited regenerative capacity of the adult mammalian heart. In addition to cell-based approaches and in situ cardiac reprogramming, significant interest has been focused on genetic and small molecule–based strategies to enhance endogenous cardiomyocyte proliferative potential. A recent study in Nature suggests, for the first time, that microRNAs may have the ability to induce cardiomyocyte proliferation and cardiac regeneration in adult mice.