Plasmids pABD1 and pGH1, which contain selectable marker genes conferring respectively resistance to kanamycin and to chlorsulfuron, were used to transform mesophyll protoplasts of Lycopersicon esculentum and Lycopersicon peruvianum by electroporation. It was possible to recover resistant colonies and calli in both cases with a relative transformation efficiency ranging from 0.2% to 2%. Plants were regenerated from four independent clones of L. peruvianum resistant to kanamycin. For two of them, Lp1Kr and Lp6Kr, the presence of the foreign gene was confirmed by molecular analysis. Plants of the clone Lp1Kr were crossed with wild type and shown to transmit the kanamycin resistant trait as a single Mendelian character.