Introduction. The most susceptible to lead is the hematopoietic system of hematopoietic organs due to lead inhibition of heme and globin synthesis and cytotoxic effect on the membrane of Mature red blood cells. The aim of study was to evaluate the informative value of the study of erythrocyte and reticulocyte parameters determined on modern hematological analyzers in patients working in contact with lead during medical and biological monitoring. Materials and methods. 45 employees of the lead battery processing plant and 30 persons of control group were examined. The level of lead in the blood was determined by atomic absorption spectrometry, δ-ALA in the urine-by the reaction of pyrol formation with acetylacetone in terms of gram of creatinine, the study of hematological parameters was performed on a Sysmex HT-2000i analyzer. Statistical processing of the results was performed using the program STATISTICA 10.0. Results. Significant changes in erythrocytic (RDW) and reticulocytic (RET, IRF, LFR, MFR, HFR, RET-He) parameters, erythropoietin in workers in contact with lead compared to the control group, changes in MCV, MCH, RDW, RET indicators in the group working in dynamics after 2 years were revealed. Associations of hematological parameters with biomarkers of exposure and effect (lead level in blood and ALA in urine) were revealed. Conclusions. Assessment of erythrocyte (MCV, MCH, RDW) and reticulocyte parameters (RET% and their distribution by maturity) in dynamics during periodic medical examinations of workers in contact with lead allows us to detect the development of hematological disorders at early stages.