The arterial supply of the human tibia in 50 specimens, ranging in age from 4 to 87 years, has been studied by the arterial perfusion method. The tibia is supplied principally by branches of the anterior and posterior tibial arteries and the peroneal artery, with additional contributions from the inferior genicular arteries, the middle genicular artery and from the infrapatellar branch of the descending genicular artery. There is a continuous arterial anastomosis in the periosteal network on the non-articular surface of the tibia. The segmental periosteal ring arteries dividing into ascending and descending branches, connect with the branches from above and below to form the longitudinal anastomoses along the anterior, medial and the lower one-third of lateral tibial borders. The epiphyseal-metaphyseal regions are copiously supplied by vessels entering from the periphery and by the nutrient artery. With the fusion of the epiphyseal plate, a free anastomosis is established between the epiphyseal and metaphyseal nutrient vessels. The whole of the marrow and the inner two-thirds or three-quarters of its cortex are supplied by the nutrient artery. The outer third or fourth of the cortex is supplied by the periosteal vessels. Because the cortical longitudinal and transverse capillary systems are profusely anastomosed with each other and with the periosteal and endosteal circulatory networks, the blood can flow in either direction, depending on physiological conditions.The clinical significance of the arterial distribution to the tibia is briefly discussed.