This paper provides information on the vertical distribution of cadmium and lead in the sediments, the amounts of the elements in the surface- and rain water, in selected fish organs, contents of their alimentary tracts, and in some plant species of the świdwie Lake ecosystem. The levels and distribution of the analysed metals in the lake sediments gave evidence of their anthropogenic origin. The distribution of cadmium and lead in the organs and alimentary tracts of fishes, and especially the low level of the elements in fishes and plants suggests that the metals are linked to the abiotic components of the lake environment and they are not easily accessible for the organisms. The best bio-indicators of the pollution-level with cadmium and lead in the lake ecosystem are: the rudd, Scardinius erythrophtalmus L. and the roots of cattail, Typha angustifolia.