The organization of the intrahepatic biliary tree was studied in three dimensions by scanning electron microscopic (SEM) corrosion casts, in normal and cholestatic rat liver. In the normal liver the observation revealed the features of the biliary passages from the bile canaliculi to the canaliculo-ductular junction, to the ductules and the bile ducts, confirming previous SEM observations. In cholestatic liver, the modifications and the proliferation of bile ductules appear clearly. Resin flow from canalicular to sinusoidal network was never observed. The method was found to be very useful in the evaluation of the architecture of the intrahepatic biliary tree, under normal as well as under pathological conditions.