Increased neurohormonal activation is a key feature of heart failure (HF). Copeptin is a surrogate marker for proarginine vasopressin and the prognostic value of copeptin has been reported for multiple disease states of both nonvascular and cardiovascular etiology. Elevated plasma copeptin in HF has been associated with adverse outcomes such as increased mortality, risk of hospitalization and correlates with the severity of HF. Copeptin may add prognostic information to already established predictors such as clinical variables and natriuretic peptides in HF. In addition, copeptin has been found to be a superior marker when compared with BNP and NT-proBNP in HF patients discharged after hospitalization caused by HF or myocardial infarction (MI). The optimal use of copeptin in HF remains unresolved and future appropriately sized and randomized trials must determine the role of copeptin in HF as a marker of adverse outcomes, risk stratification or as a target in biomarker-guided therapy with arginine vasopressin-antagonists in individualized patient treatment and everyday clinical practice.