By repeated measurements in each of ten normal subjects and ten patients with mild intermittent claudication, the performance of three transcutaneous oxygen tension (PtcO2) test in the diagnosis of obliterative peripheral arterial disease was studied. PtcO2 resting value, PtcO2 response to oxygen breathing and PtcO2 reperfusion response after tourniquet obstruction were all measured on the dorsum of the foot. We found that PtcO2 resting values were not different between patients and controls, while responses to 100% oxygen breathing and reperfusion responses differed significantly between the two groups. The most prominent difference between the two groups was observed in the latency of PtcO2 rise after reperfusion. Therefore the reperfusion response test may have a place in the assessment of claudication by PtcO2 measurement.