OBJECTIVE:: To explore the peripheral leucocytic messenger RNA (mRNA) expression of glycogen synthase kinase-3β (GSK-3β) gene in Alzheimerʼs disease (AD) patients. METHODS:: Using TaqMan relative quantitative real-time polymerase chain reaction, we analyzed leucocytic gene expression of GSK-3β in 48 AD patients and 49 healthy controls. Clinical data of AD patients were also collected. RESULTS:: The mRNA expression level of the GSK-3β gene was significantly higher in the AD group (3.13 ± 0.62) than in the normal group (2.77 ± 0.77). Correlational analyses showed that the mRNA expression level of GSK-3β gene in AD patients was associated with the age of onset (P= 0.047), age (P= 0.055), and Behavioral Pathology in Alzheimerʼs Disease Rating Scale total score (P= 0.062) and subscores: aggressiveness score (P= 0.073) and anxieties and phobias score (P= 0.067). Through multivariate regression model, older age, higher anxieties and phobias score and aggressiveness score were associated with higher mRNA expression level of GSK-3β gene. CONCLUSION:: In AD patients, the mRNA expression level of the GSK-3β gene is increased and may be related to age and behavioural pathology in AD.