Male ICR mice were given dietary Cd at three different levels (50, 100 and 200 ppm) for 85 days. At the end of this period, they showed a marked accumulation of Cd in the liver and kidney. In addition, there was also an increase in Zn and a decrease in Fe in these organs. The concentration of Cu in these organs; however remained unchanged. Serum cholesterol decreased in the Cd-100 and Cd-200 groups, but hepatic cholesterol did not. There was a positive correlation between serum cholesterol and serum Cu or Zn but not between serum cholesterol and serum Zn/Cu. Serum triglyceride was increased slightly but not dignificantly by the Cd exposure. A significant negative correlation between serum and hepatic triglyceride was found. These alterations of serum and hepatic lipids were discussed in relation to the essential metals (Cu, Zn and Fe).