The purpose of the present study was to compare neurotransmitter amino acid concentrations in the cerebrospinal fluid (CSF) and CSF/plasma ratios in 21 patients with dementia with Lewy bodies (DLB) and 26 matched controls. To this purpose, we used an ion-exchange chromatographic method. DLB patients exhibit higher CSF concentrations of asparagine (+25%) and glycine (+21%) compared to a control group, whereas no differences in CSF/plasma ratios were found between both groups. On the other hand, no alterations in concentrations of glutamate, aspartate and GABA were detected in CSF of patients compared to a control group. There was no correlation among amino acid levels and CSF/plasma ratios with age, age of onset, body mass index, duration of the disease or scores of the Mini Mental State Examination, UPDRS and Hoehn and Yahr stage. These results suggest a possible role of glycine and asparagine in the pathogenic mechanism of dementia with Lewy bodies.