Achilles tendon is the strongest and the thickest tendon in the human body and plays a major role in the biomechanics of lower extremities. Although it is known to resist a tractive force of 1 ton, it is reported to be one of most common tendons to rupture. The fibers of the Achilles tendon are not aligned strictly vertically and they display a variable degree of spiralization. This structure provides both a stronger tendon and less interfiber friction. Kager`s fat pad is an adipose tissue, which occupies the Kager`s triangle and sometimes extends up to the soleus muscle. This fat pad is also in close relationship with retrocalcaneal bursa and has important biomechanical roles. Haglund`s deformity, retrocalcaneal bursitis, ruptures and enthesopathies are most common encountered pathologies of the Achilles tendon. Proper diagnosis and management of these pathologies requires a precise knowledge of their etiologies and the anatomy of the Achilles tendon. The main blood supply of the Achilles tendon comes from a recurrent branch of the posterior tibial artery and the least vascularized part of the Achilles tendon is mid one-third.