Aim To investigate the relation and clinic significance between carotid atherosclerosis （CAC） and the level of serum midkine （MK） in patients with essential hypertension （EH）. Methods The survey was conducted in 110 patients selected from the special care medical center of Naval General Hospital of PLA between February 2009 and October 2012. Based on the results of carotid ultrasound and blood pressure, the patients were divided into three groups: EH with CAC group （n48）, simple hypertension group （n42） and normal control group （n20）. The level of serum MK was determined by ELISA method. The level of serum insulin and the insulin resistance index （IRI） were also determined. Then the related data were analyzed. Results In EH with CAC group, the level of serum MK and IRI were significantly higher （P<0.05）. In patients with EH, the level of serum MK, systolic blood pressure （SBP） and IRI were positively correlated with carotid intima-media thickness （IMT） （r0.512, 0.466, 0.408, all P<0.01） the level of serum MK was positively correlated with IRI （r0.618, P<0.01）. Logistic regression analysis showed that the level of serum MK, IRI, course of hypertension, and SBP were related to carotid atherosclerosis closely. Conclusions