The aim of this study was to evaluate the effects of low-dose chronic lead, mercury and cadmium exposure on the reproductive potency of Wistar rats and on their progeny. The number of litters and the number of newborns in rats exposed to Pb and Hg were significantly higher compared to controls, whereas between Cd exposure group and controls there was almost no difference. In contrast, the survival rate of the weanlings decreased in the order Cd>Pb>Hg and in all exposed groups was higher than in controls. The results suggest that an increase in reproduction rate early after intoxication onset may disclose certain reactive adaptation mechanisms. The number of weanlings appears to be a sensitive marker in reprotoxicity tests.