Aneurysms of the Valsalva sinus (aortic sinus) can be congenital or acquired and are rare. They are more common among men than women and among Asians than other ethnic groups. Nonruptured aneurysms may be asymptomatic and incidentally discovered, or they may be symptomatic and manifest acutely with mass effect on adjacent cardiac structures. Ruptured Valsalva sinus aneurysms result in an aortocardiac shunt and may manifest as insidiously progressive congestive heart failure, severe acute chest pain with dyspnea, or, in extreme cases, cardiac arrest. Although both ruptured and nonruptured Valsalva sinus aneurysms may have potentially fatal complications, after treatment the prognosis is excellent. Thus, prompt and accurate diagnosis is critical. Most Valsalva sinus aneurysms are diagnosed on the basis of echocardiography, with or without angiography. However, both electrocardiographically gated computed tomography and magnetic resonance (MR) imaging can provide excellent anatomic depiction, and MR imaging can provide valuable functional information.