ELABELA (ELA), previously classified as a "noncoding" RNA, is a new endogenous peptidic ligand of apelin receptor (APJ/APLNR), a class A (rhodopsin-like) G protein-coupled receptor. It has been identified to play a crucial role in diverse biological processes, especially in the normal and pathological cardiovascular system. In comparison with APJ's first ligand apelin, ELA may play a key role at different time points or heart regions. In this review, we summarized the roles of the ELA-APJ signaling pathway in cardiovascular system development and diseases.