A total of 24 patients harboring arteriovenous malformations (AVMs) in either the dominant hemisphere (n = 12) or the nondominant hemisphere (n = 12) were examined neuropsychologically. When compared with 24 matched normal control subjects, the AVM patients demonstrated differential degrees of impairment in verbal or visuospatial processing, depending on whether the lesion involved the dominant or nondominant hemisphere. As predicted, most compelling were the findings of cognitive deficit associated with the hemisphere contralateral to the AVM relative to matched normal control subjects. Evidence of higher cortical dysfunction contralateral to the residing AVM is discussed in the context of cerebrovascular steal.