Choline acetyltransferase in temporal cortex was evaluated as a marker of cholinergic function in autopsied dementia cases (9 vascular dementia [VaD] cases, 12 "mixed" VaD and Alzheimer disease [AD] cases, 10 AD cases, 12 control subjects). Patients with AD (t = 2.5, p = 0.02) and "mixed" VaD and AD (t = 3.8, p = 0.001) had greater cholinergic deficits than age-matched control subjects and patients with "pure" VaD. The absence of cholinergic deficits in "pure" VaD may be relevant to the pharmacologic treatment of these patients.