A study was performed to evaluate the effects of lead and its sites of accumulation, at tissue and cell level, in tobacco plantlets in vitro exposed to the heavy metal and to reveal possible differences in immobilization depending on variety and/or type of tobacco. N. tabacum varieties Burley IST Bu23, Burley IST G94-2, Bright IST G19, Bright IST G 165, Perustitza IST Pr61 and Perustitza IST P2B were in vitro cultured on MS medium. Then 50 days old plantlets were exposed, (10 days) to four lead nitrate rates (distilled water, 0.01, 0.1 and 1 mM Pb(NO3)2). Scanning and Transmission Electron Microscopy observations were carried out on leaf, stem and root. SEM analyses were unable to detect significant differences among the different treatments and the varieties, as occurred with macroscopic observation. However, at the highest concentration we may note the evident increase in shininess of the leaf stoma. Nevertheless, TEM observations showed morphocytological disorders, with a progressive alteration of cell organelles. Generally it was observed that the extent of damage caused by lead increases, when lead exposure level increases for all organs examined. Among the tobacco varieties analysed, G94-2 seems to be less sensitive to lead treatment. Only the roots and in part the stems allow accumulation sites to be localized. Hardly ever is this possible for the leaves for any of the Pb concentrations used. With regard to the roots data from X-ray qualitative and quantitative microanalysis to SEM revealed an increase in phosphorus and a considerable decrease in potassium, which seem linked to the increase in lead for all varieties except for G94-2. For this variety, despite detecting a decrease in potassium we noted no increase in phosphorus." This research is carried out with financial support of the Commission of the European Communitie, Tobacco and Information and Research Found, project 96/T/35 "Monitoring and minimizing heavy metals contents in tobacco". It does not necessarily reflect the views of the Commission and in no way anticipates its future in this area.