ALAD recovery (% ALA-D) is an effect biological marker sensible and specific for lead exposure even at low levels of blood lead concentration (Pb-B). Currently, the health of children environmentally exposed to chemicals has been subject of great attention. Many studies have found an inverse association between Pb-B and bone growth. The homeostasis of calcium, which is regulated by PTH, Vitamin D and Calcitonin, can have some aspects of its metabolism affected by lead. There are few studies concerning effect biomarkers to lead and their relationship to bone metabolism. The aim of this study is to evaluate the effect of lead in the bone metabolism in children from 0 to 16 years old through the determination of %ALA-D in blood and to correlate it with PTH levels and nutrition factors. This study was conducted in João Goulard Community, Rio de Janeiro. The biological samples were collected in CSEGSF/FIOCRUZ Laboratory, simultaneously to the application of questionnaires to evaluate alimentary frequency as well as social and economical characteristics. ALA-D and PTH assay was made through spectrofotometric and quimioluminescent techniques, respectively. There were 65 children evaluated, who presented low ingestion of micronutrients (calcium, vitamin D and iron), as well as low consumption of calories, and 22% presented microcytic and hipocromic anemia. Average levels of Pb-B, %ALA-D and PTH were 5.51m d/dL, 40% and 42,5r g/mL, respectively. %ALA-D presented correlation with Pb-B (r=0,460; p<0,001). About 5% of children presented levels of Pb-B above 10m g/dL, and 56.7% presented % ALA-D above reference value. A significant correlation was observed between %ALA-D and PTH (r=0,270; p=0,05). An important association was found in what concerns the exposure biological markers, the PTH, the urinary calcium, the hematimetrics indexes and the alimentary frequency, demonstrating that lead is able to modify the levels of PTH and the calcium-mediated processes. These data are showing risk to children in relationship lead exposure and it is possible to cause neurological and hematological damages.