Chest radiographs and computed tomographic images of 110 patients with chronic aortic dissection were retrospectively reviewed. Among these, calcification of false channel wall was observed in 12 cases (about 10%). Stanford type A dissection was noted in 5 cases and type B in 7 cases. Calcified false channel wall may closely simulate intimal calcification of atherosclerotic aneurysm on chest radiographs and sometimes even on CT. Careful observation of CT images with and without contrast enhancement is helpful to correctly identify the site of calcifications in the false channel wall, true channel wall, and intimal flap in the individual cases. In 3 cases calcification was present mainly in the false channel wall with no or only minimal calcification in the true channel wall. These cases may suggest that the endothelialized false channel lumen may develop atheromatous changes much more rapidly than the true lumen. According to advances in surgical and medical treatment of acute aortic dissection, radiologists may encounter cases of chronic aortic dissection with increasing frequency. Full recognition of this potential pitfall in the diagnosis of aortic dissection is important to avoid confusion.