This study assessed the concentration of lead in umbilical cord blood of 64 newborns to pregnant women who live in Huancayo (commercial and urban zone) and La Oroya (mining-smelting zone of Central Peru) and its impact on hemoglobin level, length, weight and Apgar score at birth. Crosssectional study was conducted in the Hospital II Essalud of La Oroya and Huancayo Regional Hospital between November 2003 and April 2004, when La Oroya smelter was operating normally. Quantification of blood lead level was performed by atomic absorption spectrometry with graphite furnace in the Peruvian Institute of Nuclear Energy. Biological sampling responded to Iyengar and Rapp protocols. Mean lead concentrations in Huancayo and Oroya newborns were 18.03 and 22.96μg/dL respectively (p=0.016), and these values were 1.8 and 2.3 times higher than the critical level suggested by the CDC and the WHO (10μg/dL). Hemoglobina levels for Huancayo and La Oroya newborns were 18.3 and 16.9g/dL (p=0,000). Anemia was observed only in Oroya newborns (9.38%). By regression analysis, the inverse association was evident between lead content in umbilical cord blood and the hemoglobin level, weigth, length and APGAR score at birth.