Right heart catheterization is a diagnostic procedure in which a small catheter is inserted into central vein and maneuvered into right side of heart, in order to measure right heart pressure, pulmonary hemodynamics and cardiac output. There is no universally accepted indication of right heart catheterization but it is used as diagnostic test which includes pulmonary hypertension evaluation, congenital heart study, heart-lung transplantation and others. It is also widely used in critical care unit in patient with cardiogenic shock. Zeroing and referencing of the pressure system are the important steps before starting the procedure in order to ensure the correct evaluation of hemodynamic parameters. It is utmost important to avoid errors in pressure measurement especially pulmonary capillary wedge pressure because it can complicate the differentiation of pulmonary arterial hypertension from other pulmonary hypertension disorders and lead to wrong diagnosis. In conclusion, clinical correlation and standardization of right heart catheterization are warranted to ensure the accuracy of diagnosis and establishing prognosis of patients with pulmonary arterial hypertension.