The principal route of entry of the pollutant metal cadmium (Cd) into plants is via uptake from soil, where it is present at 0.15 to 0.2 ppm. Leguminosae are weak accumulators of Cd; Gramineae , Liliaceae, Cucurbitaceae, and Umbelliferae accumulate moderately this element; in contrast, Cruciferae , Compositae, Chenopodiaceae and Solanaceae like tobacco concentrate Cd from soil by a factor of as much as ten on a dry weight basis. Tobacco translocates most of the absorbed Cd to the leaves. 75 % to 81% of the Cd is translocated to the leaves in Nicotiana rustica and N. tabacum , against 25 to 28 % to the leaves in maize. Cd is first adsorbed on the surface of the roots by ion exchange at negatively charged sites, and then diffuses in the apoplast where it can be chelated. Then the metal is absorbed by the symplast via the same pathway as calcium, before it's translocation to other organs. Phytochelatins and metallothioneins which are both Cd-chelators, are often induced by heavy metal intoxication. Phytochelatins are Cd-binding peptides, derived from glutathion, and found in certain yeasts and fungi, as well as in algae and plants. Metallothioneins are small cysteine-rich proteins, with an higher Cd affinity than phytochelatins. These proteins are found in all mammals and the majority of vertebrates and invertebrates, as well as in certain yeasts, fungi and procaryotes. Recently, metallothioneins have also been found in certain plants. The goal of the work presented here was to modify tissue partitioning of accumulated Cd in transgenic industrial tobacco plants as a potential application of genetic transformation of plants. In order to reduce leaf Cd levels, we have introduced into tobacco chimeric genes encoding a mammalian metallothionein, which is in some cases in fusion with the beta-glucuronidase (GUS). We have obtained transgenic plants expressing strongly these genes, with significant decrease in leaf Cd levels correlated with an accumulation of the Cd in the roots and in the stems.