Glucose dysmetabolism has been consistently associated with an increased risk of cognitive disorders, and brain insulin resistance could play a role in Alzheimer's disease (AD) pathogenesis. Recent evidence suggests that cerebrospinal fluid (CSF) biomarkers may reflect the brain pathology in AD. We have investigated the relationship between CSF concentrations of amyloid-β peptide 1-42 (Aβ 1-42 ), total tau, and phosphorylated tau (ptau-181) and plasma and CSF glucose levels in a cohort of 94 newly diagnosed non-diabetics AD patients. We report that CSF Aβ 1-42 level was inversely associated with CSF to plasma glucose ratio (Spearman's coefficient = −0.27, p = 0.008). This relationship remained after adjustment for age, gender, body mass index, hypertension, and MMSE score (β [SE] of linear regression = −0.93 [0.37], p = 0.01). In stratified analysis, this relationship was observed only in patients who did not carry the apolipoprotein E4 allele. No significant relationship was found between glucose levels and total tau or phosphorylated tau 181. These results support the idea that a link between glucose dysmetabolism and the amyloid pathway may exist in the pathogenesis of AD.