BACKGROUND Takotsubo syndrome (TTS), a form of acute transient heart failure, has been associated with severe complications and considerable mortality rates. N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP) might serve as a marker to identify high-risk patients but has not yet been investigated regarding prognostic implications in TTS. Aim of this study was to determine the short- and long-term prognostic utility of NT-proBNP in patients with TTS. METHODS The predictive value of admission NT-proBNP was assessed in an international, multicenter study including 177 consecutive TTS patients. Predefined endpoints were 30-day major adverse cardiac events (MACE) consisting of all-cause death, cardiogenic shock, and pulmonary edema as well as long-term mortality in median 2.3 years after the acute event. RESULTS Stratification according to median admission NT-proBNP (4511 pg/ml) resulted in significantly higher 30-day MACE [22.5 versus 9.1%; odds ratio (OR) 2.90, 95% confidence interval (CI) 1.20-6.99 p = 0.015] and long-term mortality rates [16.3 versus 9.4%; hazard ratio (HR) 2.72, 95% CI 1.13-6.56 p = 0.021] in patients > median. The best admission NT-proBNP cutoffs to predict 30-day MACE and long-term mortality were determined at 5560 and 8178 pg/ml respectively, with subsequent improved risk stratification for short-term MACE (OR 3.61, 95% CI 1.49-8.72; p = 0.003) and long-term mortality (HR 4.40; 95% CI 1.85-10.44, p < 0.001). Multivariate regression analysis identified admission NT-proBNP as an independent predictor of 30-day MACE (p < 0.001) and long-term mortality (p = 0.012). CONCLUSIONS Admission NT-proBNP is an independent predictor for short- and long-term adverse events in TTS patients and, therefore, a useful marker for risk stratification immediately at presentation.