In electron microscopic observation of a liver biopsy obtained from a hepatitis B surface antigen-positive patient, noncoated core particles were occasionally seen budding into the hepatocytic cisterni and many Dane particles were found in the pericanalicular vesicles of hepatocytes. Noncoated core particles were also localized in clusters within the bleb of microvilli. There were some core particles being protruded from microvilli into the lumen of bile canaliculi by budding. These findings suggest hepatitis B virus being released from the hepatocyte to the bile canaliculi by two different modes; through vesicle by reversed phagocytosis and from the microvilli by budding.