Twenty patients suffering from peripheral obliterative arterial disease underwent metabolic and haemorheological study. The femoral arteriovenous differences in lactate and oxygen extraction varied with the severity of the ischemic process, as assessed clinically. In patients with claudication lactate release and oxygen extraction were comparable with those in the control group while were significantly increased in Fontaine’s III and IV stage patients. Moreover this latter group showed the most relevant changes in whole blood viscosity and filterability. Such findings bring a further contribution to the correlation between the regional circulatory imbalance and changes in haemorheological parameters.