A 74-year-old woman was admitted for right coronary angioplasty. During the procedure, she complained about chest pain, and contrast injection showed an iatrogenic dissection of the ascending aorta. A contrast computed tomography (CT) scan confirmed the diagnosis via visualization of a large non-circulating false lumen, which involved nearly the entire ascending aorta. The patient remained hemodynamically stable and asymptomatic while receiving medical therapy alone. Another CT scan performed 3 days later showed complete regression of the false lumen. This case suggests that uncomplicated iatrogenic dissection of the ascending aorta, even when large, may be managed successfully by medical therapy.