The capacity of the heart to heal after a myocardial infarction is not enough to restore normal cardiac function. Fortunately, delivery of therapeutics such as stem cells, growth factors, exosomes and small interfering ribonucleic acid (siRNA), among other bioactive molecules, has been shown to enhance heart repair and improve cardiac function. Furthermore, new delivery systems for these therapeutic agents have enhanced their regenerative and cardioprotective potential. In particular, nano- and microparticles (NPs and MPs) are promising. These systems may be administered directly in the infarcted myocardium or reach the heart after intravenous injection due to the enhanced permeability and retention effect or active targeting. Thus, NPs and MPs have made it possible to administer a wide range of potential drugs, including therapeutic molecules and/or stem cells, and evidence in favor of their use has been reported in several preclinical studies. Here, we review the studies done over the last 5 years using NPs and MPs loaded with therapeutics for repairing cardiac tissue after a myocardial infarction, and discuss some of the advances, challenges and future prospects in this field. In addition, we address the application of NPs and MPs for cardioprotective purposes.