The cytoplasmic microfilaments of hepatocytes, especially in the pericanalicular area, were examined in 25 liver biopsy specimens obtained from 15 patients with intrahepatic cholestasis. About 25 days after the onset of jaundice an increase in bile canaliculi dilation was noted, though an increase in amount of microfilaments was less conspicuous in comparison with the next stage. At about 55 days an increase in number was seen around dilated canaliculi. At about 100 days microfilaments decreased in amount and the dilation of canaliculi became less evident, while swollen microvilli protruded into the canaliculi with their microfilaments irregularly arranged. An increase of microfilaments in hepatocytes, particularly in the pericanalicular area, might be a reflection of the secretion of bile.