In the present study the role of the traditional biomarkers of exposure and effect on haeme system during lead exposure was analysed: the opportunity of introducing new biomarkers such as lead and delta-aminolevulinic acid in plasma was also evaluated, especially by considering the current levels of exposure. The population in study was constituted by 371 males owning to different production fields and selected by five national units. The results suggest caution in the use of lead in plasma as a biomarker of lead exposure in the biological monitoring procedures, mainly in reason of its great variability affecting in particular the sampling time and the pre-analytical treatment of the sample. The other biomarkers were well correlated between them and with the exposure biomarkers for lead in blood >300 microg/L, suggesting the BEI to which the protection of workers exposed to lead would be guaranteed (instead the actual of 600 microg/L).