Our study was conducted on 36 patients (four cases were excluded) with complex congenital heart disease; all patients were subjected to ECHO, MRI and cardiac angiography. The results are summarized as follows: Regarding the confluence of the pulmonary artery: MRI was superior to TTE as a non-invasive tool in diagnosing PA confluence in CHD and was comparable to the angiography results. Regarding identification of MAPCAS ; the results were unsatisfactory, both angiography and MRI did not obtain all data required separately, MRI added to the angiography the number of MAPCAs and angiography added the anatomical details of the MAPCAs. In summary, although MRI and Angio depicted different diameters in assessing the MPA, LPA and RPA but there was no statistical significance. On the contrary to TTE; when compared with MRI there was a statistical significance. The results of this study indicate that MR imaging and angiography are complementary imaging techniques. With experienced observers, MR imaging is nearly equivalent to angiography for assessment of pulmonary artery size.