To examine the effects of meso-2,3-dimercaptosuccinic acid (DMSA) on developmental toxicity resulting from exposure to lead in utero, female albino mice were exposed to lead by drinking water contaminated with lead acetate for 4 weeks. After the cessation of lead exposure, female mice were supplemented by gavage with saline solution, DMSA, or DMSA and calcium as well as ascorbic acid from the fourth day of gestation until parturition, respectively. Lead levels (blood, liver, and bone) were measured at birth. Pups were then tested about neural development including surface righting reflex, cliff avoidance and air righting reflex. The markers of physical maturation, such as body weight, pinna unfolding, incisor eruption, and eye opening were also recorded. DMSA treatment decreased blood lead levels of pregnant mice, however, increased lead levels in both liver and bone of fetus, and delayed the early physical and neural development of offspring. Calcium and ascorbic acid reduced the transfer of lead to fetus. In conclusion, DMSA treatment during pregnancy enhances lead-induced fetal developmental toxicity.