Three cases of hereditary hemorrhagic telanglectasia (HHT) with cerebrovascular malformation are presented. Previous reports of HHT have given little attention to its association with cerebrovascular malformation, despite frequent neurological symptoms in patients with HHT. Eleven other cases of HHT with neuropathologic or radiographic evidence of cerebrovascular malformation have been reported in the literature. We think that this association may be more frequent than previously suspected. The subtlety of the symptoms in HHT is stressed, and it is suggested that patients with cerebrovascular malformation be examined carefully for HHT, and vice versa.