Lead is a naturally occurring element that has multipurpose applications and has been used since early civilizations being widespread in the environment. Lead is not biodegradable and its continual use has contaminated air, water, and soil. It is highly toxic affecting the whole body and is particularly harmful to newborns and children, adversely affecting cognitive development and behaviour. For children aged <6 years the Centres for Disease Control and Prevention (CDC), in 1991, defined an elevated blood lead level (BLL) as >or= 10 microg/dl, but evidence exists for subtle effects at lower levels. From the 1980s, the international trend has been to phase-out lead content in gasoline, which has contributed to substantially lower average BLLs in these populations. However, its complete elimination from gasoline in Portugal was not reached before 1999. Our group has from long participated in BLL surveillance programs to help target prevention efforts and monitor progress toward reducing BLLs in Portugal. Here are presented the studies carried out with children.