Arterial segments of fifteen mongrel dog kidneys were studied by preparing corrosion casts with the help of Takilon. The arterial system of the kidney in the mongrel dog is clearly divided into the dorsal and ventral vascular area vascularized by the dorsal and ventral branch. The borders of these two areas correspond to the horizontal plane wich divides the kidney into two almost identical and fully independent halves. The anastomoses between the interlobar arteries of the same vascular area or anastomoses between the dorsal and ventral branch have not been noticed. Each dorsal and ventral ramus in its intrarenal course divided into inter lobar, arcuate and interlobular branch, respectively. Dorsal branch gived off 6.3 arteria interlobares and ventral branch gived rise to 6.1 arteria interlobares on avarage.