This study compared 32 patients with ischemic vascular dementia (IVD) to 32 patients with probable Alzheimer's disease (AD) on select language and verbal memory tests. The IVD and AD patients were individually matched on the basis of age, dementia severity, years of education, and gender. The IVD patients had poorer verbal fluency, but better free recall, fewer recal intrusions, and better recognition memory than the AD patients. Relationships between the neuropsychological measures and radiological indexes of cortical and subcortical pathology were also examined. Number of infarcts, white-matter lucency, and ventricular enlargement correlated with some of the neuropsychological measures; cortical atrophy correlated with most of the measures. The findings suggest that neuropsychological deficits in IVD may be related to dysfunction of frontal-subcortical circuits, although an associated degenerative cortical process may also be involved.