The digits of ten donkeys were dissected carefully for determination the sites of the tendenious and ligamentous attachments. Moreover 300 proximal phalanx, 200 middle phalanx and 150 distal phalanx were examined for the presence of the exostosis. The percentage of the exostosis of the proximal phalanx (30%) is higher than that of the other two phalanges, as the sesamoidean apparatus attaches mainly to the proximal phalanx, which exposes this bone to greater compression load. On the other hand, the percentage of exostosis is low in distal phalanx, because the tendinous and ligamentous attachments of this bone are protected by the hoof. It is found that most of the digital exostosis were observed at or around the area of attachments of tendons or ligaments. Therefore it is suggested that sprains or tears of tendons or ligaments causing exostosis in donkeys.