Agrobacterium-mediated transformation of tobacco leaf disks with two Agrobacterium tumefaciens (A.t.) strains LBA4404 and EHA105 and four plasmids pCAMBIA1201, pCAMBIA1301, pCAMBIA2301 and pCAMBIA3201 was used for the introduction an uidA reporter gene and corresponding plant selection genes (hpt, npt or bar gene) into tobacco (Nicotiana tabacum L. cv. Havana 38). Our goal was to study the efficiency of transformation protocols with tobacco plant. The transformation efficiency of each combination of two Agrobacterium strains and four plasmids was evaluated by histochemical analysis of b -glucuronidase (GUS) activity in transformed tobacco plants. The highest rate (P ? 0.05) of GUS activity was observed with tobacco infected with A.t. strain LBA4404 carrying pCAMBIA1301 (33.2%) and pCAMBIA1201 (27.8%). When tobacco was infected with A.t. EHA105, there was no regeneration of transformed tobacco plants (except with pCAMBIA1301, 21.7%). The A.t. strain EHA105 was therefore observed to be less appropriate for transformation of tobacco leaf disks.