Abstract: Objective To investigate serum adiponectin level in patients with Alzheimer’s disease (AD) and its correlation with the patients’ cognitive function. Methods This case-control study was conducted in 90 patients with a highly probable diagnosis ofAD, who were divided into mild, moderate and severe group saccording to the MMSE score. Ninety healthy subjects matched for age and gender with the AD patients were selected as the control group. The serum levels ofadiponectin in the participants were detected using enzyme-linked immunosorbent assay. Results Serum adiponectin level was significantly lower in the AD group than in the control group (P<0.05). Of the 3 subgroups of the AD patients, the moderate and severe AD groups showed significantly lower serum adiponectin level sthan the control group (P<0.05), but the difference in adiponectin levels was not significant between the mild AD group and the control group (P>0.05); serum adiponectin levels also differed significantly among the 3 subgroups of AD patients (P<0.05). Serum adiponectin level was positively correlated with the MMSE score in the AD patients (r=0.683, P<0.001). Conclusion Serum adiponectin levels are reduced in AD patients and associated with the degree of cognitive impairment.