Coronary artery disease (CAD) arising from atherosclerosis remains the most common cause of death and morbidity worldwide, although its risk factors, such as hypertension, dyslipidemia, and diabetes, have been individually treated with increasingly improved outcomes. Therefore, it is important to develop diagnostic and therapeutic windows for CAD. Many classical vasoactive hormones, inflammatory cytokines, and oxidative products have been implicated as potential biomarkers. Our recent studies have shown that high levels of the pro-atherogenic vasoactive agents, serotonin and urotensin II, which are potent vasoconstrictors, can be used as biomarkers for CAD. In subsequent trials, we unraveled anti- and pro-atherogenic roles for more recently identified peptides. Anti-atherogenic peptides include the adipocytokine adiponectin, the neuronal growth factor heregulin-β₁ (neuregulin-1 type I), the incretin hormone, glucagon-like peptide-1 (GLP-1), and a peptide recently identified by an in silico approach, salusin-α. Atherogenic roles have been demonstrated by cellular, animal, and clinical experiments, which indicate that human adiponectin, heregulin-β₁, GLP-1, and salusin-α attenuate the development of atherosclerotic lesions by suppressing macrophage foam cell formation via down-regulation of acyl-CoA:cholesterol acyltransferase-1. Circulating levels of these peptides in the blood are markedly decreased in CAD patients compared with those in non-CAD patients. Receiver operating characteristic curve analyses have shown that salusin-α is the most useful biomarker for detecting CAD among the four peptides examined. Therefore, salusin-α, alone or in various combinations with heregulin-β₁, adiponectin, and/or GLP-1, is a candidate biomarker for predicting CAD. Further, anti-atherogenic peptides could potentially serve as useful therapeutic targets for atherosclerotic cardiovascular diseases.