Male Wistar-rats were used to investigate the liver glycogen pattern quantitatively under normal conditions and after oral application of CdCl2 (dosage: 50 ppm or 150 ppm) solved in drinking-water. The duration of the experiment was 1,3,6, or 12 month. The control animals have the lowest liver glycogen content at the beginning of the spring. During the summer, the liver glycogen content is increased and reached the highest level at the ending of the year. Under cadmium influence the liver glycogen content was diminished. The cadmium-effect is influenced by seasons. There is a small cadmium-effect in the time of a low liver glycogen content at the beginning of the spring. With the increasing liver glycogen content in the June, temporary the cadmium-effect is increasing too. The strongest cadmium-effect was obtained in the phase of the cadmium-effect is increasing too. The strongest cadmium-effect was obtained in the phase of high liver glycogen accumulation at the ending of the year.