Background: Assessment of prognosis is of major importance when deciding on a therapeutic strategy in patients with pulmonary arterial hypertension (PAH). Objectives: The aim of this study was to investigate the prognostic value of pulmonary hemodynamics during exercise and changes during treatment in patients with PAH. Methods: Consecutive incident patients (n = 49) with PAH undergoing right heart catheterization at rest and during a constant workload cycle exercise in supine position were included. Predictors of survival were identified at baseline using Cox proportional hazard regression models in a univariate analysis unadjusted and adjusted for age and gender. Results: During a median follow-up period of 42 months, 13 (27%) of the 49 patients studied died. Two predictors of death were found: rest-to-exercise changes in heart rate and systolic pulmonary artery pressure. Adjusted hazard ratios were 0.92 (95% CI 0.86–0.99) and 0.93 (95% CI 0.88–0.99), respectively. These 2 variables were correlated with each other (r = 0.55, p < 0.001). Conclusions: Rest-to-exercise changes in heart rate and systolic pulmonary artery pressure measured at diagnosis are predictors of survival in patients with PAH. These measurements taken from an exercise test reflect right ventricular function.