Aim. The aim of the study was to assess the relationship between lead levels in children's blood and the development of social disorders. Method. Lead levels were measured in every child's blood test and following on from that the influence of this toxin on children's behaviour was assessed. Manfred Cierpka questionnaire was used as the assessment tool examining children's family relationships and Children's Health Questionnaire Parent Form-28 was used to assess the subjects' health profile. Results. The statistical analysis revealed a statistically significant relationship between lead concentration in the child's blood and whether or not the child was able to meet social expectations (p=0.018), form affective relationships (p=0.046), its nervousness (p=0.024) and a generally lower assessment of his/her behavior in comparison with the peer group (p=0.024). Conclusions. Neurotoxic influence of lead on the developing child's organism results in developmental disabilities in its behaviour. These dysfunctions can lead to disorders in the child's social development and they can hinder its functioning. An increased concentration of metal toxins in the child's blood can be responsible for difficulties in meeting social expectation, which in turn is connected with increased nervousness and disorders in forming relationships. Children facing these problems often receive negative marks for their behaviour in comparison with the peer group. Such difficulties can lead to the child's social exclusion and predispose it to making antisocial or criminal decisions in the future.