In a group of 33 patients affected by diabetes mellitus transcutaneous oxygen tension (PtcO2) was measured by means of a Clark polarographic electrode. Patients were divided into 3 groups according to the symptoms and/or to the clinical findings: group A: paresthesia (22 limbs); group B: claudication (6 limbs); group C: rest pain and/or necrosis (13 limbs). Moreover, group C was divided into: C1 trophic neuropathy lesion (7 limbs) and C2 trophic ischemic lesion (6 limbs). Our data point out that there is a statistically significant difference between mean PtcO2 values in limbs with trophic ischemic lesions versus the other 3 groups. Therefore, PtcO2 is particularly indicated and useful in the study of diabetic patients with peripheral vascular disease where integrates the other instrumental noninvasive techniques.