Background: CHD is a major health problem in pediatric population. It is associated with abnormal hemodynamic load and neurohormonal activation. Which leads to pulmonary hypertension causing myocardial injury. So, it needs timely intervention. Cardiac troponins are specific for myocardial injury. HscT I enhances accuracy for diagnosis of myocardial injury even in early stage of Pulmonary Hypertension. In recent years role of HscT I suggested to be useful in evaluation of PAH due to CHD in children. Objectives: To analyze the role of HscT I as a diagnostic tool for PAH due to CHD in Children. Methods: This prospective cross-sectional study was conducted in Pediatric cardiology department, BSMMU over a period of 1 year. The study included total 54 patients with moderate to large VSD/PDA. Patients were selected according to inclusion and exclusion criteria. Results: Total 54 cases was divided into two group PAH group (n=27) and non-PAH (n=27) group. Among PAH group 20 patient (74.1%) had VSD and 7 patient (25.9%) had PDA. In non PAH group 15 had VSD (55.6%) and 12 had PDA (44.4%). The mean troponin I level was significantly higher in PAH group than non-PAH group (0.03052±0.0511 vs. 0.0087±0.0075, p=0.03). Conclusion: In this study, there was significant difference between HscT I level of PAH group and non-PAH group and significant positive correlation between HscT I level and mean PAP. As a marker of myocardial injury, HscT I can be a predictor of raised pulmonary arterial pressure in children with post tricuspid left to right shunt.