Numerous studies indicate that certain genetic polymorphisms modify lead toxicokinetics. Metallothioneins are protective against the toxicity of many metals, including lead. The aim of this study was to determine whether the maternal metallothionein 2A (MT2A) -5 A/G single-nucleotide polymorphism is related to the lead levels in maternal blood, placental tissue and cord blood in 91 pregnant women and their newborns.