Type 2 diabetes mellitus (T2DM) significantly increases the risk of atherosclerotic cardiovascular disease. Ankle brachial index (ABI) and carotid artery stenosis are non-invasive indicators of generalized atherosclerosis. This study aimed to explore the risk factors for ABI and carotid artery stenosis and discover which factors simultaneously influence both conditions in T2DM. The study included a total of 101 patients with T2DM. ABI was performed via Doppler ultrasound, and both common carotid arteries were examined via ultrasound to obtain the percentage of carotid artery stenosis. A negative correlation was noted between the ABI and the percentage of carotid artery stenosis (p = 0.043). ABI correlated significantly negatively with waist circumference (p = 0.031), total cholesterol (p = 0.003), low-density lipoprotein (LDL) cholesterol (p = 0.003), and C-reactive protein (CRP) (p = 0.017), whereas the percentage of carotid artery stenosis correlated with the smoking habit (p = 0.017) and CRP (p = 0.042). The best model for predicting the ABI value (R2 = 0.195) obtained from stepwise regression analysis included waist circumference, LDL cholesterol, triglycerides, and CRP, while the best model for the percentage of the carotid artery stenosis (R2 = 0.112) included smoking and CRP. CRP influenced the ABI value with a negative parameter estimate of −0.008962 (p = 0.053) and the percentage of the carotid artery stenosis with a positive parameter estimate of 0.443655 (p = 0.006) relative to a one-unit change of it, presenting the negatively significant impact of CRP on the association between carotid artery stenosis and low ABI. Our results suggest that CRP is the most important risk factor that connects ABI and carotid artery stenosis, which are important non-invasive indicators of generalized atherosclerosis in T2DM.