control and cross-sectional studies) published in English carried out on children within the last 5 years, measuring lead exposure and health outcomes related to ADHD. Seventeen studies met the inclusion criteria: 5 of these studies found no association between lead exposure and ADHD whereas the remaining 12 studies showed positive associations, even though not all of them were homogeneous in terms of exposure periods considered or ADHD diagnosis. To conclude, the evidence from the studies allowed us to establish that there is an association between lead and ADHD and that even low levels of lead raise the risk. However, there is still a lack of longitudinal studies about the relationship between lead exposure and the development of ADHD. Given the potential importance for public health, further research that includes the entire potential risk factors for ADHD in children must be encouraged.