In summary, nanowired human cardiac organoids significantly augment the therapeutic potential of hPSC-CMs for heart repair. While cardiac organoids have been used for cardiac tissue engineering applications, this study reveals e-SiNWs as a class of biocompatible, conductive nanomaterials that facilitate contractile and noncontractile benefits in hPSC-CM transplantation. Given the emerging clinical applications of hPSC-CMs to treat infarcted hearts, these results have direct translational impacts for conductive nanomaterials in cardiac cell therapy and implications in other conductive tissues (e.g., skeletal muscle and neuronal tissues).