We evaluated six patients with vertebrobasilar dolichoectasia (VBD) comparing clinical presentation with magnetic resonance (MR) and computed tomography (CT) imaging. MR diagnosed the condition as well as CT in all cases, but proved superior to CT in delineating the anatomical relationship of the vessels to the neural structures. MR proved especially useful in cases of VBD-associated hydrocephalus and posterior fossa masses. A coexisting tumor was diagnosed by MR in one case.