The ankle-brachial index is the ratio between systolic arterial pressures measured on the arms and the ankles. It is a highly sensitive and specific test for detecting peripheral arterial occ­lusive disease (PAOD). Decreased ABI is a marker of PAOD progression; it predicts complications of PAOD and mortality. ABI correlates well with the presence of coronary and cerebrovas­cular atherosclerosis. Therefore, it is a good non-invasive surrogate marker of (coronary) atherosclerosis. It is clinically relevant that patients with decreased ABI have an increased risk of cardiovascular events and mortality. Furthermore, decreased ABI measured in elder­ly persons is associated with disturbed mobility and gait not directly associated with intermittent claudication. Overall, it appears that ABI, due to its simplicity and a high predictive value, should become a routine test (along with the standard risk factor assessment) for estimating cardiovascular risk. It makes sense that in case a decreased ABI is found, measures to retard further progress of atherosclerosis should be applied.