The effects of arteriosclerosis obliterans on the hemodynamic changes that occur during walking are largely unknown. For this reason, the authors measured blood pressure by transducer from the posterior tibial artery and vein at both ankles in 23 patients with arteriosclerosis obliterans of different severity and at the left ankle in 8 normal subjects. Radial artery pressure was also measured, and the differences between mean radial and ankle arterial pressures (pressure gradient) and between mean arterial and venous ankle pressures (foot perfusion pressure) were calculated. All measurements were made simultaneously and continuously during standing, treadmill walking at five different speeds, and during recovery. Compared with the normal subjects, the patients exhibited a greater pressure gradient and lower ankle arterial pressure and foot perfusion pressure at rest. During walking and recovery these intergroup hemodynamic differences were markedly enhanced, and ankle venous pressure was lower in the patients than in the normal subjects. In the patients the hemodynamic pattern depended on disease severity at rest and on both disease severity and walking speed during walking and recovery.