In a group of 43 school-children living near a zinc plant, the test of granulocyte viability by the method of Cocchi et al, the lead level by flame atomic absorptiometry, and the level of erythrocyte zinc-protoporphyrin by the fluorimetric method were determined in peripheral blood. The mean result of the granulocyte viability test was 6.49%. In 18 children, the proportion of abnormal granulocytes was raised abnormally above 6.0%. The lead level was in the range from 14.1 to 53 micrograms/dl, and the level of erythrocyte ZPP was from 0.3 to 2.1 micrograms/g Hb. No correlation was found between the results of the granulocyte viability test and the blood lead level. The result of a comparison with the ZPP value was of borderline significance (p = 0.05).