In order to set up a system for production of recombinant proteins using suspension cell culture of Nicotiana tabacum cv. Bright Yellow 2 (BY-2), in vitro culture and genetic transformation protocols of such cells were optimised at the laboratory of Plant Cell Biotechnology, Institute of Biotechnology. The experiments indicated that the development rate of BY-2 cells depended on initial cell concentrations. The best culture condition was the formula F5 with 1:20 dilution at the starting point (2.5 mL of initial cells/50 mL culture medium) which reached the exponential phase after 5 days and had maximum biomass of 1.206 g/mL after 9 days. Agrobacterium tumefaciens-mediated transformation procedure of BY-2 cells was optimised by monitoring transient gusA gene expression. There is a positive correlation between the amount of BY-2 cells and the density of Agrobacterium tumefaciens in coculture medium. The transformation efficiency was the highest at formulars 0.6-1, 0.8-4 and 1.0-5 (bacteria OD-plant cell formular).