Background: Accurate evaluation of extra cardiac and intra cardiac anomalies in congenital heart diseases (CHD) is vital for diagnosis and treatment. Trans-thoracic echocardiography (TTE) is the classical choice for children suspected to have CHD because TTE is safe, readily available and its capacity to perform Doppler flow studies therefore can measure hemodynamic parameters. Plus its ability to evaluate intra cardiac abnormalities like atrial septal defect and ventricular septal defect. Therefore, owing to its lower spatial resolution and limited acoustic window; it is not precise in evaluation of extra cardiac abnormalities. Aim of the Work: to evaluate the advantage of recent advances of ECG gated MDCT in diagnosis of congenital heart disease in pediatrics and assessment of associated extra cardiac abnormalities within the great vessels in comparison with echocardiography findings. Patients and Methods: The current study was carried out on 36 patients in Radio-diagnosis Department, Faculty of medicine, Ain Shams University and specialized private radiology centers. The patients were referred from pediatric hospital, cardiology clinic with their echocardiographic reports to radio-diagnosis department, cardiac imaging unit with a view to execute ECG-gated multi-slice CT of the heart & extra-cardiac great vessels. Results: In this study aortic anomalies represent the most common extra-cardiac anomalies accounting for 36.5% of our cases while comprising: Supravalvular aortic stenosis; 4.3%, Aortic CoA; 26.1%, arch anomalies with vascular rings; 52.2% and finally anomalous coronary arteries; 17.4%. By Using MDCT we were able to delineate eight cases of right aortic arch (RAA).Two of them with aberrant left subclavian artery (ALSCA) adding to two cases of left aortic arch with an aberrant right subclavian artery (ARSCA). On the other hand ,TTE failed to identify 6 cases of RAA with a sensitivity 75%, specificity 100%, NPV 96.61% and one case of ALSCA with a sensitivity 50.0%, specificity 100%, NPV 98.41% .Regarding coronary anomalies , Cardiac CTA succeeded in characterization of origin and course of all coronary abnormalities encountered in our study encompassing 4 cases specifically anomalous LAD from right coronary sinus running a prepulmonic course anterior to RVOT , RCA from LAD and single coronary artery adding to LCX-RV coronary fistula. While TTE failed to depict two cases of the coronary anomalies with a sensitivity of 50%, specificity 100%, PPV 100% and NPV 96.83%. Conclusion: CTA can provide the confident detection and exclusion of extra-cardiac vascular abnormalities with superb anatomical description which was feasible with a sensitivity 98.41%, specificity 99.76%, PPV 96.88% and NPV 99.88%.