We investigated the relationship between peripheral arterial disease (PAD) and renal function in patients with type 2 diabetes mellitus (T2DM). We enrolled 2057 hospitalized patients with T2DM and measured kidney function and ankle-brachial index (ABI). The estimated glomerular filtration rate (eGFR) was derived using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and ABI was grouped as low (<0.9), low-normal (0.9-1.09), normal (1.1-1.3), and high (>1.3). Logistic regression was used to evaluate the associations of eGFR with ABI. Generally speaking, the ABI was negatively correlated with systolic blood pressure, fasting C-peptide, total cholesterol, and low-density lipoprotein cholesterol while positively correlated with body mass index (P < .05 to <.01). Only a low ABI was positively correlated with eGFR (P < .01). In addition to the association of the ABI with cardiovascular events, stroke, and PAD, ABI may also predict the change in renal function in patients with T2DM.