Increased amounts of CSF pyruvate and lactate were found in patients with AD and patients with vascular dementia (VaD). In the AD group, CSF pyruvate values did not show any overlap with those obtained in controls; within the VaD group, the highest values were observed in possible VaD cases. A significant correlation between the severity of dementia and these biochemical parameters was also observed in both AD and possible VaD. The similarities of CSF pyruvate patterns observed in AD and possible VaD patients implicate a neurodegenerative component in this VaD subgroup.