Objectives: Few tools exist that provide objective accurate prediction of short-term mortality risk in patients presenting with acute heart failure (AHF). The purpose was to describe the accuracy of several biomarkers for predicting short-term death rates in patients diagnosed with AHF in the emergency department (ED). Methods: The Biomarkers in ACute Heart failure (BACH) trial was a prospective, 15-center, international study of patients presenting to the ED with nontraumatic dyspnea. Clinicians were blinded to all investigational markers, except troponin and natriuretic peptides, which used the local hospital reference range. For this secondary analysis, a core lab was used for all markers except troponin. This study evaluated patients diagnosed with AHF by the on-site emergency physician (EP). Results: In the 1,641 BACH patients, 466 (28.4%) had an ED diagnosis of AHF, of whom 411 (88.2%) had a final diagnosis of AHF. In the ED-diagnosed HF patients, 59% were male, 69% had a HF history, and 19 (4.1%) died within 14 days of their ED visit. The area under the curve (AUC) for the 14-day mortality receiver operating characteristic (ROC) curve was 0.484 for brain natriuretic peptide (BNP), 0.586 for N-terminal pro-B-type natriuretic peptide (NT-proBNP), 0.755 for troponin (I or T), 0.742 for adrenomedullin (MR-proADM), and 0.803 for copeptin. In combination, MR-proADM and copeptin had the best 14-day mortality prediction (AUC = 0.818), versus all other markers. Conclusions: MR-proADM and copeptin, alone or in combination, may provide superior short-term mortality prediction compared to natriuretic peptides and troponin. Presented results are explorative due to the limited number of events, but validation in larger trials seems promising.