Background: Type 2 diabetes mellitus (T2DM) poses an increased risk for cardiovascular disease (CVD) through atherosclerosis. The apolipoprotein B (apoB)/apolipoprotein A-I (apoA-I) (ApoB/ApoA-I) ratio is a powerful predictor of atherosclerotic CVD and is associated with carotid atherosclerosis (CA) in T2DM; however, this association had never been studied in our setting. This study set out to determine the prevalence of CA and its correlation with ApoB/ApoA-I and non-high-density lipoprotein cholesterol (non-HDL-c)/high-density lipoprotein cholesterol (non-HDL-c/HDL-c) ratios among patients with T2DM in Southwestern Uganda. Methods: A cross-sectional study conducted at Mbarara Regional Referral Hospital included 212 ambulatory patients with T2DM aged ≥40 years. Socio-demographic, clinical, and behavioral characteristics were determined. Fasting blood samples were collected for measuring serum glucose, Apo B, Apo A-I, and the routine lipid profile. The apoB/apoA-I ratio and the non-HDL-c/HDL-c ratio were calculated. Carotid intima-media thickness (CIMT) was measured bilaterally at three points by high-resolution B-mode ultrasound. A mean value of six measurements from the right and left carotid arteries was used as a measure of CIMT. Carotid atherosclerosis was defined as a mean CIMT≥1.0 mm. A stepwise multivariate regression analysis and Pearson’s correlation were used to assess the association and correlation of CIMT with clinical factors, apoB/apoA-I, and non-HDL/HDL-c ratios. Results: The prevalence of CA was 35.9%. Age ≥55 years (OR 3.1; 95% CI:1.4 – 7.1; pConclusion: There is a high prevalence of CA among patients with T2DM. The non-HDL-c/HDL-c ratio was significantly associated with high CIMT but not the apoB/apoA-I ratio.