The effect of short-term occupational exposure to lead on erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity and serum cholesterol was studied in 40 male workers of a lead and zinc foundry. All parameters were measured just before employment and after 172 +/- 21.3 days of work. Genetic deficiency of erythrocyte G6PD was observed in 5/40 subjects. Among G6PD normal subjects, increases in enzyme activity followed any change (increase or decrease) in blood lead. At the pre-employment test, serum cholesterol parameters did not show any correlation with GOD activity or blood lead, and they were not affected by exposure. Cholesterol values observed among all the GOD-deficient subjects were within the range of the rest of the study population.