Heart-type fatty acid-binding protein (H-FABP) is a reliable marker of myocardial injury and was recently identified as a predictor of outcome in acute pulmonary embolism. The aim of the present study was to investigate the prognostic value of H-FABP in chronic thromboembolic pulmonary hypertension (CTEPH). In total, 93 consecutive patients with CTEPH were studied. During long-term follow-up (median duration 1,260 days, interquartile range (IQR) 708-2,460 days), 46 (49%) patients had an adverse outcome, defined as CTEPH-related death, lung transplantation or persistent pulmonary hypertension after pulmonary endarterectomy (PEA). Baseline H-FABP levels in plasma ranged from 0.69-24.3 ng x mL(-1) (median (IQR) 3.41 (2.28-4.86) ng x mL(-1)). Cox regression analysis revealed a hazard ratio of 1.10 (95% confidence interval 1.04-1.18) for each increase of H-FABP by 1 ng x mL(-1), and continuous elevations of H-FABP emerged as an independent predictor of adverse outcome by multivariable analysis. PEA was performed in 52 patients and favourably affected the long-term outcome. Kaplan-Meier analysis revealed that patients with baseline H-FABP concentrations >2.7 ng x mL(-1), the median value of the biomarker in the surgically treated population, had a lower probability of event-free survival after PEA. Heart-type fatty acid-binding protein is a promising novel biomarker for risk stratification of patients with chronic thromboembolic pulmonary hypertension.