Objective: To investigate the relationship between serum asprosin levels and carotid intimamedia thickness (CIMT) in patients with type 2 diabetes mellitus (T2DM). Methods: A total of 99 patients with T2DM were enrolled in this study. According to the 2009 Guidelines for Vascular Ultrasound, all patients were divided into two groups, including 46 patients with thickening CIMT (CIMT≥1.0 mm, thickening CIMT group) and 53 patients with normal CIMT (CIMT<1.0 mm, normal CIMT group). Clinical and biochemical parameters were tested and the serum asprosin was analyzed by ELISA. The atherosclerosis index of plasma (AIP) was calculated to assess the degree of atherosclerosis. Spearman correlation analysis was used to analyze the correlation between serum asprosin and CIMT, AIP and biochemical indicators. Logistic regression analysis was used to analyze the influencing factors of CIMT thickening. Results: The serum asprosin in the thickening CIMT group was higher than that of the normal CIMT group (P<0.01). Correlation analysis showed that the serum asprosin of T2DM patients was positively correlated with CIMT, triglyceride and AIP (r=0.317, 0.266, 0.285, P<0.01) and was negatively correlated with apolipoprotein A (r=-0.242, P =0.016); CIMT was positively correlated with age, duration, neck circumference, waist circumference, systolic blood pressure and asprosin (r=0.577, 0.390, 0.203, 0.229, 0.295, 0.317, P<0.05 or P<0.01). Logistic regression analyses demonstrated that as serum asprosin increases, the risk of CIMT thickening increases in patients with T2DM. Conclusion: Asprosin may play a role in the occurrence and development of CIMT thickening in T2DM patients.