Early diagnosis of acute coronary syndromes (ACS) allows for efficient risk stratification, appropriate targeted therapies, and faster patient disposition within crowded emergency departments. Although only troponin testing is recommended for routine use in the 2007 American College of Cardiology/American Heart Association guidelines for non-ST-elevation ACS, emerging data support selected use of other biomarkers, including B-type natriuretic peptides (BNPs) and C-reactive protein. There remains a need to identify additional biomarkers in ACS to enhance risk stratification and to help guide therapeutic decisions in this increasingly complex area of cardiovascular medicine. Cardiac biomarkers may help to diagnosis ACS before cardiomyocyte necrosis, to influence the decision for early invasive treatment, and to provide a means of monitoring response to therapy. In this review, we assess new data in ACS with respect to troponins, BNPs, myeloperoxidase, fatty acid-binding protein, and monocyte chemoattractant protein-1. We also discuss novel biomarkers including growth deficient factor-15 and neopterin.