Appropriate parameters are needed for the monitoring of children with pulmonary arterial hypertension (PAH). Various biologic markers seem to be of use in adults with PAH. No data are available on their value in children with PAH. In this study, the relation between serum markers, functional parameters, and hemodynamic variables in pediatric PAH and their ability to predict survival is determined. Serum N-terminal pro brain natriuretic peptide (NT-proBNP), uric acid, norepinephrine, and epinephrine were measured and correlated with invasive hemodynamics, functional parameters, and outcome in 29 pediatric patients with PAH who visited a tertiary reference center for pediatric PAH between 1997 and 2005. NT-proBNP correlated with functional class (R = 0.36; p = 0.03) and 6-min walking distance (6MWD) (R = -0.53; p < 0.001). Uric acid correlated with mean pulmonary arterial pressure, pulmonary vascular resistance, and cardiac index (R = 0.63, p = 0.01; R = 0.71, p = 0.03, and R = -0.65, p = 0.007, respectively). After initiation of treatment, NT-proBNP decreased. This decrease correlated with an increased 6MWD. Finally, norepinephrine and NT-proBNP levels were highly predictive for mortality. In this series of children with PAH, biologic markers were correlated with hemodynamics and functional capacity, as parameters of disease severity. The data indicate that these markers can be used to monitor treatment effects and predict mortality in pediatric PAH.