The objective of the present study was to determine the lead (Pb) concentration in umbilical cord blood and its relationship with anthropometric measurements of 55 newborns. Umbilical cord blood was collected immediately after delivery for the determination of Pb and hemoglobin (Hb) concentrations. Hb was measured with the HemoCue system and blood Pb concentration was determined by graphite furnace atomic absorption spectrophotometry. We observed an inversely proportional correlation of cord blood Pb concentrations with newborn weight (beta=-0.275; p=0.048) and length (beta=-0.460; p=0.003). The mechanisms whereby Pb reduces newborn size are unknown. One possible explanation would be a reduction in fetal thyroid hormones caused by the presence of Pb. However, further studies are necessary to confirm this hypothesis.