Most data on heart failure biomarkers have been derived from patient cohorts with chronic disease. However, risk prediction in patients admitted with acute decompensated heart failure (ADHF) remains a challenge. ADHF is not a single disease: it presents in various manners, and different causes may underlie ADHF, which may be reflected by different biomarkers. Soluble suppression of tumorigenicity 2 (ST2) has been shown to be a strong independent predictor of short-, mid-, and long-term outcome in ADHF. Furthermore, combining biomarkers may help further improve the prognostic power of ST2. The ProBNP Investigation of Dyspnea in the Emergency Department study showed that elevated plasma levels of ST2 together with elevated levels of 4 other biomarkers have clear incremental values to predict outcome in ADHF. The Multinational Observational Cohort on Acute Heart Failure study is an international collaborative network that recruited 5,306 patients hospitalized for ADHF that demonstrated that ST2 and midregional pro-adrenomedulin had independently strong value to predict 30-day and 1-year outcome in patients with ADHF. The Multinational Observational Cohort on Acute Heart Failure study also showed that C-reactive protein plus ST2 better classified risk in patients with ADHFs than ST2 alone. Combining biomarkers for risk prediction or risk stratification might have clinical and more importantly pathophysiological meaning.