Tests were carried out on the levels of cadmium, copper, iron and zinc in selected organs (liver, kidneys and spleen) of bank voles (Clethrionomys glareolus, Schreber, 1780) caught in autumn 1998 and 1999 in a number of forests situated at varying distances east and south of Kraków. All the results were compared with the levels of these metals present in voles caught from a control area of Borecka Forest. Cadmium content was determined with a graphite tray, using a Perkin Elmer AAnalyst 800 atomic absorption spectrophotometer, after wet digestion of samples in a mixture of inorganic acids (HNO3 : HClO4). The concentrations of physiological elements (Cu, Fe, and Zn) were analyzed using the flame method of an IL-251 atomic absorption spectrophotometer. The levels of heavy metals present depended on the organ being tested and the area in which the rodents were caught. The relationships between the content of these elements and the age and sex of the animals were also observed.