Delayed wound healing and, less commonly, wound breakdown are significant complications following open Achilles tendon repair. Skin perfusion over the Achilles tendon may be reduced when the ankle is plantarflexed. The aim of this study was to analyse skin perfusion over the Achilles tendon with the ankle in varying degrees of plantarflexion in 20 volunteers. Skin perfusion was determined by measuring the transcutaneous skin oxygen pressure (tcPO2) using the Novametrix TcO2M 860 monitor. Measurements were taken at the medial edge of the Achilles tendon in 20 volunteers. Skin perfusion was maximal with the ankle plantarflexed to 20 degrees. With plantarflexion beyond this skin perfusion was reduced. At 40 degrees plantarflexion skin perfusion was reduced by up to 49% (mean 35%, range 27% to 49%). We conclude plantarflexion beyond 20 degrees reduces skin perfusion in the region of the Achilles tendon. Though this study was performed on non-operated cases, and is thus limited, the findings may have clinical implications with regard to cast position following Achilles tendon repair.