Abstrak : Type 2 diabetes mellitus is a metabolic disease characterized by hyperglycemia that occurs due to abnormalities in insulin secretion, insulin function, or both. Type 2 diabetes concerns can manifest as macrovascular issues such as heart failure and microvascular issues such as peripheral arterial disease Ankle Brachial Index is a simple method to diagnose and assess the severity of Peripheral Arterial Disease and to evaluate cardiovascular prognosis in the general population. This study aims to determine the association between ABI value and the severity of heart failure in patients with type 2 diabetes mellitus. This study was a cross-sectional study at Dr. Wahidin Sudirohusodo Hospital and Hasanuddin University Hospital. In our study, we Included patients ages 40-60 years with heart failure and type 2 diabetes mellitus diagnosed. Ankle Brachial Index was a comparison of ankle artery systolic blood pressure values with brachial artery systolic blood pressure. Our results show, there was a significant positive correlation between ABI and heart failure (p<0.05) with a moderate coefficient correlation (R= 0.289). We also analyzed that participants with HFrEF had significantly higher moderate ABI degrees (p<0.05). This study found there was a significant association between moderate ABI degrees with severity of heart failure. The low level of ABI was proportional to the low level of Left Ventricle Ejection Fraction.