Chromosome and biochemical studies were conducted for 18 healthy females occupationally exposed to lead in the manufacture of electrical storage batteries and in 12 comparable female controls. Biochemical indicators of dose (blood lead) and effect (erythrocyte protoporphyrin, delta-aminolevulinicacid dehydratase activity of red blood cells) were significantly different in the two groups. Cytogenetic studies were performed on lymphocytes cultured for 2 and 3 days with phytohemagglutinin to investigate the possible effect of culture time with respect to yield of chromosome aberrations. The results showed significantly increased rates of metaphases with chromatid and chromosome aberrations--excluding gaps--in the exposed vs. controls at both culture times. The yield of abnormal metaphases was higher in the 3-day than in the 2-day cultures, both in the exposed and controls; the difference was moderately significant for controls, while highly significant for those exposed. These results demonstrate the occurrence of increased numbers of abnormal metaphases also in women occupationally exposed to lead, as previously found in males.