Delivery of hydrogels to the heart is a potential strategy for reducing scar burden following myocardial infarction. The gelatin methacryloyl (GelMA) bioadhesive hydrogel… could address limitations of previously reported hydrogels. The elasticity of GelMA was adjusted to match that of mouse myocardium. GelMA was then applied to the epicardial surface of mouse hearts at the time of experimental myocardial infarction (MI). GelMA was delivered as a liquid precursor and was polymerized into a solid scaffold in situ using visible-spectrum light. Left ventricular scar burden and survival were measured three weeks after MI. GelMA application was performed safely and was associated with significantly improved post-MI survival. GelMA application was also associated with reduced scar burden and improved left ventricular function.