Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a technique where a balloon is advanced through the common femoral artery and temporarily inflated for treatment of cardiac arrest or non-compressible haemorrhage. The aim of this study was to measure intravascular distances relevant for correct placement of the REBOA catheter using computer tomographic (CT) scans. In a series of CT scans of the aorta from 100 patients diagnosed with severe aortic stenosis planned for transcatheter aortic valve implantation, we measured the intravascular distance from the insertion site in the common femoral artery to two potential zones for placement of the REBOA catheter; between the left subclavian artery and the celiac trunk (Zone 1), as well as between the aortic bifurcation and the distal take-off of the renal arteries (Zone 3). The mean (± SD) intravascular distance from the femoral artery to intra-aortic Zone 1 was 36 (± 2.5) cm for the lower border and 60 (± 4.1) cm for the upper border, respectively. For intra-aortic Zone 3, the mean (± SD) intravascular distance was 21 (± 2.1) cm to the lower border and 31 (± 2.3) cm to the upper border. Calculated potentially safe intervals for placement of the REBOA in Zone 1 was with 99.7% likelihood between 43 and 48 cm. No similar potentially safe interval could be calculated for Zone 3. According to this cohort study of patients with severe aortic stenosis, the balloon of the REBOA catheter should travel intraarterially between 43 (lower limit) and 48 cm (upper limit) from the site of insertion into the common femoral artery, which would lead to correct placement in intra-aortic Zone 1 in 99.7% of cases. In contrast, no potential safety interval could be similarly defined for insertion in Zone 3.