The purpose of this study was to assess the reliability of multidetector CT (MDCT) angiography and three-dimensional (3D) reconstruction in patients with coarctation of the aorta. Sixteen patients (median age, 2 months; range, 15 days to 28 months) with suspected coarctation of the aorta underwent both color Doppler echocardiography (CDE) and MDCT. In addition to the CT axial slices, 3D reconstructions such as volume rendering and multiple planar reformation were used to diagnose coarctation and associated cardiac abnormalities. The sensitivities of diagnosis were evaluated compared with MDCT and echocardiography and surgical findings. Sixteen cases were diagnosed as coarctation of the aorta by MDCT. This included hypoplasia of the aortic arch (n = 5). The results were confirmed at the time of surgery. Diagnosis sensitivities of coarctation were 87.5% for axial and 100% for both multiplanar and 3D volume-rendered images. Moreover, MDCT was able to clearly display the location and extent of the coarctation. Focal defects were observed in 14 cases, and diffuse defects in 2 cases. The sensitivity of MDCT diagnosis for coarctation of the aorta was 100%, which was higher than that of CDE (87.5%). Ventricular septum defect was diagnosed by MDCT in 11 cases, with 1 missed, and the sensitivity was 91.7% (11/12), which was lower than that of CDE (100%; 12/12). In addition, six patients had patent ductus arteriosus. Two patients in this study had collateral vessel formation. We conclude that CTA with 3D reconstruction represents a reliable noninvasive technique for the assessment of coarctation. It may serve as a noninvasive diagnostic tool before intervention or surgical treatment.