It was found in sheep that the left cranial vena cava formed by two brachiocephalic veins terminated in coronary sinus together with left azygous vein and great as well middle cardiac veins. The right azygous vein escapes into right atrium. In dog two cranial venae cavae were observed. The right vena cava terminated in the right atrium, the left vena cava escapes together with cardiac veins into widened coronary sinus.