An understanding of torsion in the human Achilles tendon would assist in more efficient percutaneous tendon lengthening procedures. Tendoachilles torsion was measured on 16 human cadaver specimens. Significant torsion was found in all tendons studied. The authors developed a method to quantify the degree of tendon torsion, explore a possible relationship to external anatomical landmarks, and suggest that the development of tendoachilles torsion closely follows postnatal development of the tibia.