Caspian miniature horse is a rare small horse in Iran. In this horse, Brachiocephalic trunk originates from the craniodorsal of the convex part of the aortic arch. It supplies the head, neck, forelimbs and cranial part of the thoracic cavity. In this reseach topographical location of brachiocephalic trunk arising from the aorta and its ramifications have been studied. Five Caspian miniature horses over two years were used in this study. The horses were euthanized by exsanguination after general anesthesia. Three horses were embalmed and two others were studied in fresh condition. The thorax was dissected and the topographical location of brachiocephalic trunk was determined relative to the ribs and intercostals spaces. The distances between branches were measured using ruler and caliper. The results showed that there are general similarity and some topographical variation between Caspian miniature horse and the other horses.