Hippocampal volume and neuron number were measured using stereological techniques in pathologically confirmed dementia with Lewy bodies (n = 8), Parkinson's disease only (n = 4), and controls (n = 9). We, and others, have previously shown considerable cell loss in the CA1 and subiculum subregions in Alzheimer's disease. In contrast, these regions were spared in dementia with Lewy bodies where a selective loss of lower presubiculum pyramidal neurons was found. These findings suggest a selective loss of frontally projecting hippocampal neurons in dementia with Lewy bodies versus those projecting to temporal lobe regions in Alzheimer's disease.