The role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in the risk prediction of patients with systemic right ventricles (sRV) is not well defined. The aim of this study was to analyze the prognostic value of NT-proBNP in patients with an sRV.The prognostic value of NT-proBNP was assessed in 98 patients from the SERVE trial. We used an adjusted Cox proportional hazards model, survival analysis, and c-statistics. The composite primary outcome was the occurrence of clinically relevant arrhythmia, heart failure, or death. Correlations between baseline NT-proBNP values and biventricular volumes and function were assessed by adjusted linear regression models.The median age [interquartile range] at baseline was 39 [32-48] years and 32% were women. The median NT-proBNP was 238 [137-429] ng/L. Baseline NT-proBNP concentrations were significantly higher among the 20 (20%) patients developing the combined primary outcome compared with those who did not (816 [194-1094] vs 205 [122-357]; P=.003). In patients with NT-proBNP concentrations> 75th percentile (> 429 ng/L), we found an exponential increase in the sex- and age-adjusted hazard ratio for the primary outcome. The prognostic value of NT-proBNP was comparable to right ventricular ejection fraction and peak oxygen uptake on exercise testing (c-statistic: 0.71, 0.72, and 0.71, respectively).In patients with sRVs, NT-proBNP concentrations correlate with sRV volumes and function and may serve as a simple tool for predicting adverse outcomes.