The influence of exposure to lead and cadmium on serum concentrations of calcium, zinc, and copper was examined in 299 healthy Croatian men 20-55 years of age, including 143 workers in a lead battery factory and 156 control subjects. The interrelationship of blood lead, activity of delta-aminolevulinic acid dehydratase, erythrocyte protoporphyrin, blood cadmium, age, smoking habits, and alcohol consumption with respect to serum calcium, zinc, and copper levels was calculated by forward stepwise multiple regression. The results showed that chronic moderate exposure to lead decreased serum zinc, calcium and, to a lesser extent, copper levels. Exposure to cadmium occurred mostly through smoking and seemed to contribute to a decrease of serum zinc. All changes in serum concentrations of these essential elements were significant but remained within the normal range. The results suggest possible mechanisms of lead- and/or cadmium-induced adverse health effects in humans.