We have measured the concentration of copper and ceruloplasmin in serum of rats with carrageenan foot-oedema and in serum and exudate of rats with carrageenan pleurisy. Both serum copper and ceruloplasmin were found to increase in both models of inflammation. In these experimental conditions we have shown a strong positive correlation between copper and ceruloplasmin, in the serum of both normal and inflamed rats.