We evaluated the skull of an ancient giant deer with a deformity of one antler. The skull was found in the 1930s in the San River near Barycz, in southeastern Poland. Its dating (39,800±1000 yr BP) corresponds to MIS-3, when the giant deer was widespread in Europe. Our diagnostics for the antler included gross morphology, radiography, computed tomography, and histopathology. We noted signs of fracture healing of the affected antler, including disordered arrangement of lamellae, absence of osteons, and numerous Volkmann's canals remaining after blood vessel loss. The antler deformity appears to be of traumatic origin, with a healing component. No similar evaluation process has been described previously for this species.Kamilla Pawłowska. corresponding author,