Background/Aims: Attempting to improve the cerebrospinal fluid (CSF) diagnosis of Alzheimer's disease ( AD), the neurofilament heavy chain isoform, NfH(SMI35) was compared to other CSF markers [ total tau, phospho-tau, amyloid beta 1 - 42 (A beta 42), the ratio of amyloid beta fragments A beta 42/A beta 40 (A beta ratio)]. Methods: CSF levels were determined in patients with AD (n = 109), mild cognitive impairment (MCI, n = 25), frontotemporal dementia ( n = 15), vascular dementia ( VD, n = 41), and controls ( n = 58). Results: CSF NfH(SMI35) was elevated in AD and VD as compared to controls ( p < 0.05). Total tau was higher in AD as compared to controls ( p < 0.05). CSF phospho-tau was elevated in AD as compared to controls and VD ( p < 0.05 each). CSF A beta 42 and A beta ratios in AD were lower than in MCI and controls ( p < 0.05 each). Conclusion: The diagnostic potential of NfH(SMI35) is not superior to that of other CSF markers. Copyright (C) 2006 S. Karger AG, Basel.