In human medicine, cardiac biomarkers, such as natriuretic peptides and troponins, areroutinely used for the diagnosis, prognosis and monitoring of heart diseases. Similarly, thesebiomarkers are determined in small animals to differentiate non-cardiac from cardiac diseases.Knowledge about these biomarkers in horses is limited and requires further investigation.The first equine studies about atrial natriuretic peptide (ANP) and N-terminal ANP (NT-proANP)are promising, and show a clear correlation with atrial dimension size. Equine brain natriureticpeptides assays are still unavailable. The troponins, in particular troponin I, have been moreextensively studied in horses, and their use for the diagnosis of myocardial damage has been fullydemonstrated. They have replaced the less specific lactate dehydrogenase and creatine kinase isoenzymes,which makes the use of the last mentioned no longer legitimate. A final possible equinebiomarker is aldosterone. Reference values in horses have been established. However, in only onestudy, a correlation between aldosterone and cardiac disease has been reported.