Peripheral artery disease occurs at advanced ages and accounts for substantial cardiovascular morbidity and mortality. Monocyte chemoattractant protein-1 (MCP-1), a member of the cysteine-cysteine family of chemokines, is one of the cytokines involved in the pathogenesis of atherosclerosis and is also known as cysteine-cysteine chemokine ligand 2 (CCL2). The aim of the current study was to investigate the association between the extent of atherosclerotic peripheral artery disease (PAD) and the increase in MCP-1 level. Eighty consecutive patients who had undergone peripheral angiography for suspected PAD were included. Of these patients, 48 (60%) had hypertension, 23 (28.8%) had type 2 diabetes mellitus, 39 (48.8%) had a family history of coronary artery disease, 23 (28.8%) were cigarette smokers, and 42 (52.5%) had hypercholesterolemia. Angiography revealed that the peripheral arteries of the lower extremity were normal in 41 (51.3%) patients, whereas 39 (48.7%) patients had varying degrees of PAD. The patients were queried regarding age, gender, and atherosclerotic risk factors. The plasma MCP-1 levels were significantly lower in the patients without PAD than those in the patients with PAD (172.27 +/- 38.05 pg/mL vs. 200.87 +/- 39.31 pg/mL, p = 0.001). Moreover, as the severity of PAD increases, MCP-1 levels also increase. Thus, the plasma MCP-1 level can be used in the diagnosis of PAD and in determining the extent of atherosclerotic PAD of the lower extremities, as in determining the extent of coronary artery disease.