Magnetic resonance angiography is increasingly used as a non-invasive method in the evaluation of coarctation of the aorta. The aim of this study was to compare aortic dimensions calculated by MR angiography and those obtained by more conventional MR sequences and conventional angiography. Twenty-six consecutive patients with coarctation underwent three-dimensional MR angiography. Two independent observers retrospectively evaluated three aortic segments, site of coarctation, presence of aneurysm and existence of collateral circulation. Three aortic segments were also compared with those obtained on classical MR sequences and conventional angiography. The MR angiography was successfully performed in all showing 1 aneurysm and collateral circulation in 8 patients. Almost perfect intraobserver ( r(2)>0.91) and excellent interobserver ( r(2)>0.80) reliabilities were obtained for each aortic segment no matter which MR sequence was employed. Similarly, mainly excellent ( r(2)>0.80) concordance analysis was observed between MR angiography measurements and those calculated by either spin-echo/gradient-echo sequences or conventional angiography. This study demonstrates that MR angiography is a fast, accurate and reproducible method in the evaluation of coarctation of the aorta. It provides excellent anatomic information and reliably detects collateral vessels. Magnetic resonance angiography could probably replace the conventional angiography and will provide an additional diagnostic value in combination with turbo spin-echo sequence.