Disturbances of the vertebrobasilar circulation are often seen by the general physician and usually described as "vertebrobasilar insufficiency" (VBI). However, the term VBI is only a description of a syndrome and not a definitive diagnosis. It is emphasized that on therapeutic grounds the different etiologies and pathogenesis of this syndrome should be searched for carefully by adequate examination, including clinical findings, extra- and intracranial cerebrovascular doppler sonography, computed tomography, possibly intraarterial digital angiography and nuclear magnetic resonance imaging, and laboratory examinations. The usual diagnostic and therapeutic problems in managing a patient with "vertebrobasilar insufficiency" are discussed in the light of typical case reports.