Introduction - The objective of this study was to assess whether the time required to return to an acceptable blood lead level (Pb) had improved over time, regardless of the severity of the initial poisoning. Methods - The study population consisted of children in the Paris region, aged 6 months to 7 years, in whom an initial blood lead level (BLL) of 100 μg/L (screening BLL) was measured between January 1, 1992, and December 31, 2006, and who underwent at least one follow-up BLL measurement. The outcome of interest was the return to a Pb level <100 μg/L during follow-up in each of the three study groups (Group 2: 100 μg/L = initial Pb level <250 μg/L; Group 3: 250 μg/L = initial Pb level <450 μg/L; Group 4: screening Pb level = 450 μg/L). Results - The frequency of return to a Pb level <100 μg/L depended on the severity of the poisoning, but also on the period during which screening was conducted. In each of the poisoned groups, this frequency was significantly higher during the most recent screening period (2002–2006) compared to the earliest screening period (1992–1996). Conclusion - The time to return to a Pb level <100 μg/L gradually decreases in poisoned children. (R.A.)