In experimental cadmium intoxication 100 rats were intraperitoneally injected with single doses of 0; 5 1,0, 2,0 5,0 mg Cd++/kg body weight as well as with 14 doses of 0,25 mg Cd++/kg. In the serum of animals the level of total protein and of glycoprotein carbohydrate components was determined. After doses in the range of cadmium concentration from 0,5 to 2,0 mg Cd++/kg body weight, a statistically and significant increase of the serum level of the protein-bound hexose hexoamine and sialic acids was stated. On the other hand the dose of 5,0 mg Cd++/kg caused only the increase of hexose in comparison with values of these constituents recorded in the control group. In animals receiving multiple doses of cadmium and also in those after a single administration of 1,0 mg Cd++/kg, a significant increase of the total protein level was started. The last group revealed the highest concentrations of protein and glycoprotein carbohydrate constituents on the third day after injection of cadmium while after 14 days, amouunts of these compounds approximated the levels estimated in the control group. A univocal evaluation of the obtained results is difficult, however in the mechanism of the quantitative alterations within the glycoprotein components of rats serum, the possibility of cadmium--induced biosynthesis of these compounds should be taken into consideration.