Adult female Rana ridibunda were exposed to 200 ppm (mg/l) of cadmium (Cd as CdCl2) dissolved in water for 4, 10, and 30 days. The 96-h LC50 value for Cd was determined to 534 ppm. The concentration of Cd in the liver and kidneys and the effect of Cd on the concentrations of hepatic metallothionein (Mts) and glutathione (GSH), were estimated. Cd accumulated in the liver and kidneys in a time-dependent pattern, with the kidneys accumulating the heavy metal at higher rates after the tenth day of exposure. There was a strong positive correlation of Cd concentration between these two organs. The concentration of Mts and GSH increased with the increase of Cd concentration in the liver, following a time- and Cd-dependence pattern. The concentration of Mts and GSH was positively correlated with the concentration of Cd in the liver. Mts concentration was positively correlated with GSH concentration.