Background: The aim of current study is to investigate echocardiographic pulmonary artery wall thickness (PAWT) association with angiocardiography, echocardiography, and biochemical findings and to demonstrate its predictive role in morbidity of disease. Method: Nineteen patients with Eisenmenger Syndrome (ES) (13 females; a mean age of 12.0 +/- 4.1 [min-max 4-17] years) and 24 (16 females; a mean age of 12.1 +/- 4.3 [min-max 3-18 years]) healthy subjects as a control group were included in this prospective, cross-sectional, controlled clinical study between December, 2012 and December, 2013. PAWT were measured at the end of systole at the distal site of pulmonary valves at the parasternal short-axis. PAWT was compared with morbidity criteria of the disease such as functional class, pulmonary vascular resistance. Results: PAWT was higher in the patient group (P = 0.005) together with pulmonary arterial diameter (Z-score, P < 0.001), vena cava inferior diameter (P = 0.002), and right ventricular wall thickness (RVWT), while TAPSE was significantly lower (P = 0.002). PAWT was strongly positively correlated to RVWT (r = 0.893, P < 0.001) and moderate negatively correlated to TAPSE (r = 0.597; P < 0.011). Conclusion: PAWT can be used as an additional parameter with other echocardiographic parameters in the follow-up of Eisenmenger Syndrome in children. (C) 2015 Wiley Periodicals, Inc.