Objective: To explore the relationship between Hemoglobin Glycation Index (HGI) and carotid intima-media thickness (cIMT) in patients with type 2 diabetes mellitus (T2DM). Methods:A total of 302 inpatients with T2DM at the Affiliated Yancheng Maternal and Child Health Hospital of Yangzhou University Medical School were enrolled.The clinical?parameter?including cIMT, fasting plasma glucose (FPG), and glycated hemoglobin (HbA1c) were measured. HGI was calculated based on HbA1c and FPG, with high HGI defined as HGI ≥ 0 and low HGI defined as HGI < 0. The relationship between cIMT and HGI was observed. Results: Among the 302 patients with T2DM, 140 cases (46.4%) had thickened cIMT. The proportion of high HGI in the cIMT thickening group was higher than that in the normal cIMT group [51（36.4%）vs 31（22.8%），P< 0.05]. Duration of diabetes, smoking rate, hypertension rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), estimated glomerular filtration rate (eGFR), HbA1c, proportion of high HGI, and low-density lipoprotein cholesterol (LDL-C) were higher in the cIMT thickening group than in the normal cIMT group (P< 0.05). HbA1c and HGI were positively correlated with cIMT (r = 0.257, 0.399, P < 0.05). Logistic regression analysis showed that both HGI and HbA1c increased the risk of cIMT thickening [OR 1.511（95% CI 1.237~1.846）vs OR 1.287（95% CI 1.053~1.571）]. Conclusion: The prevalence of atherosclerosis is high in patients with T2DM, and HGI may be a new indicator of atherosclerosis risk in T2DM patients, in addition to HbA1c.