Hepatectomies in the rat can be improved using microsurgical techniques. The distribution variations of the vascular and biliar lobular branches of the liver are observed under magnification with an operating microscope and, therefore their dissection, ligation and section are more accurate. The vascularization and bile drainage of the caudate process, a liver sector located between the right lateral and caudate lobes can be identified using microsurgery. Removal of two-thirds (70%) of the liver represents the most valuable animal model of liver regeneration. The viability of the animal’s evolution after different types of subtotal hepatectomies depends on an effective identification of these vascular and biliary branches. Microsurgery also permits the use of various techniques for creating an anhepatic rat.