This study was made to investigate the structural effect of cadmium and copper on the kidney tissue of male mouse in I.C.R. strain. This was accomplished by comparing the control group with the experimental group dosed by CdCl_2 and CuSO_4. Its were administered into the abdomal cavity with a syringe in the solutoin of 1㎎, 5㎎ and 10㎎ per kilogram body weight. The change of an ultrastructure followed to the poisoning phenomenon that appered after the passing 24 hours 48 hours could be observed through the electron microscopic method. In the case of cadmium 1㎎ experimental group, the microvilli of brush border showed the tendency of becoming shorter and destroyed in comparison with control group in proximal convoluted tubule, and more ribosomes and vacuoles appeared than the control group in irregular arrangement. In the case of cadmium 5㎎ experimental group, more vacuoles were observed comparing with cadmium 1㎎ experimental group, and the cell that is between the uriniferous tubule showde the even destroyed forms and a large number of lipid droplet and vacuoles appeared. In 5㎎ copper treated group, it was showed that chromatins were slightly agglutinated, electron density of mitochondrial cristae was low and several lysosomes in the cytoplasm appeared. More agglutinations of chromatins were observed in 10 ㎎ copper treated group. So, it is considered that copper affect on the distribution of chromatins in te nucleus and inhibit mitochondrial functins. In the case of cadmium 10 ㎎ experimental group, a lot of vacuoles and high-elected ribosomes were appeared and furthermore, many lysosomes were appeared. Mitochondia was also little swelled and this phenomenon seemed that it is caused by the restriction of mitochondrial oxidative phosphorylation.