It has been suggested that nitric oxide could be implicated in the pathogenesis of Alzheimer's disease (AD). Recently Kuiper et al. reported decreased CSF nitrate levels (oxidation product that provides an indirect estimation of nitric oxide) in AD patients, assessed with a colorimetric method. However other group, using a microplate version of the Griess reaction, did not confirm these findings. We studied the CSF and plasma levels of nitrate with kinetic cadmium-reduction method in 32 AD patients and 36 matched controls. The CSF and plasma nitrate levels did not differ significantly between the two study groups. CSF and plasma nitrate levels did not correlate with age at onset and duration in the patient group. These data suggest that CSF and plasma levels of nitrate are apparently unrelated with the risk for AD.