Right heart catheterization is a unique tool not only in the diagnosis but also in the management of patients with a wide range of cardiovascular diseases. The technique dates back to the 18th century, but the biggest advances were made in the 20th century. This review focuses on pulmonary hypertension for which right heart catheterization remains the diagnostic gold standard. Right heart catheterization-derived parameters help classify pulmonary hypertension into several subgroups, assess risk of adverse events or mortality and make therapeutic decisions. According to the European Society of Cardiology guidelines pulmonary hypertension (PH) is defined as an increase in mean pulmonary artery pressure (PAPm) > 25 mmHg, whereas a distinction between pre- and post-capillary PH is made based on levels of pulmonary artery wedge pressure (PAWP). Moreover, right atrial pressure (RAP), cardiac index (CI) and mixed venous oxygen saturation (SvO2) are the only parameters recommended to assess prognosis and only in patients with pulmonary arterial hypertension (PAH). Patients with RAP > 14 mmHg, CI < 2.0 l/min/m2 and SvO2 < 60% are at high (> 10%) risk of death within the next year. The purpose of this paper is to show that RHC-derived parameters can be used on a considerably larger scale than currently recommended. Several prognostic parameters, with specific thresholds have been identified for each subtype of pulmonary hypertension and can be helpful in everyday practice for treatment of PH.