Peripheral arterial disease (PAD) is a common manifestation of atherosclerosis that is associated with systemic inflammation. The aim of our study was to assess whether plasma markers of inflammation increased after exercise in patients with PAD. The study was conducted on two groups of 20 subjects each: one group (mean age 68.4 +/- 5.09 years) was affected by PAD with claudication, while the other group consisted of healthy controls (66.9 +/- 6.1 years). Concentrations of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFalpha) were determined in plasma, in supernatants and in cells stimulated with 1 mg lipopolysaccharide in all patients. E-selectin (ES), L-selectin (LS) and P-selectin (PS) concentrations and plasma concentrations of VCAM-1 and ICAM-1 were also determined. All determinations were performed in patients at rest and after the treadmill exercise. Resting values of soluble mediators were greater in PAD patients than in controls. They increased in both groups after the treadmill test, even if post-treadmill concentrations were significantly higher in PAD patients (PAD p < 0.001 or 0.0001, controls p < 0.05 or 0.001). These results confirm that white blood cell activation is characteristic of systemic atherosclerosis and that these inflammation markers increase in conditions of hemodynamic stress.