Objectives: To compare the response to dimercaptopropanol (BAL) and calcium disodium ethylenediaminetetraacetic acid (EDTA) versus orally administered meso-2,3-dimercaptosuccinic acid (DMSA) and EDTA in children with lead poisoning. Methods: Retrospective review of medical records of children admitted to MetroHealth Medical Center with a whole blood lead (BPb) concentration of 2.17 μmol/L (45 μg/dl) or more (or less than 2.17 μmol/L and not a candidate for outpatient oral chelation) and treated with BAL + EDTA or DMSA + EDTA. In each group, the mean BPb values at the end of therapy and at 14 and 33 days after chelation were compared with pretreatment BPb by the Wilcoxon signed-rank test, whereas the Mann-Whitney U test was used to compare percentage change from pretreatment at each follow-up day between the two groups. Results: Twenty-three children received BAL + EDTA and 22 received DMSA + EDTA.The BPb values (mean ± SD) at the end of therapy and at 14 and 33 days after chelation were significantly lower than pretreatment in both groups (BAL + EDTA: 17 ± 10, 34 ± 7, 36 ± 11 vs 58 ± 14 μg/dl, p <0.02, 0.01, 0.001, respectively; DMSA + EDTA: 10 ± 4, 30 ± 10, 30 ± 14 vs 50 ± 10 μg/dl, p <0.01, 0.001, 0.01, respectively). The percentage reduction (mean ± SD) in BPb from pretreatment at the end of therapy and on days 14 and 33 after chelation did not differ between the groups (BAL + EDTA: −71.2% ± 19.8%, −40.2% ± 13.8%, −37.1% ± 17%; DMSA + EDTA: −79.9% ± 8.7%, −38.3% ± 21.6%, −37% ± 32%; p >0.20). Elevation of alanine aminotransferase and vomiting during therapy were observed more frequently in the BAL + EDTA group compared with the DMSA + EDTA group. Conclusions: Treatment with DMSA or BAL combined with EDTA results in a comparable reduction in BPb. (J Ppediatr 1997;130:966-71)