An efficient procedure was described for the transformation of the monocotyledonous oriental hybrid lily, Lilium cv. Siberia, by Agrobacterium-mediatsd genetic transformation via leaves regeneration. The leaves of leaflets which derived from bulbs were sliced into 1.0 cm long and were co-cultivated with A. tumefaciens strain LBA4404/pB2AE12, which harbored a vector carrying the neomycin phosphotransferase, DREB2A genes in the T-DNA region. The suitable genetic transformation condition was determined as follows: the bacterial concentration reached 0.5-0.6 (OD600), 15 min infection time, 20 mg·L-1 acetosyingone, and 10.6 mmol·L-1 NH4NO3 medium was used for co-cultivation 3 days, delayed 7 days for selecting by 30 mg·L-1 kanamycin containing regeneration medium. Efficient shoot regeneration was observed on MS medium supplemented with 1.0 mg·L-1 naphthaleneacetic acid, 0.5 mg·L-1 benzyladenine and 0.1 mg·L-1 Kinetin after about 6 weeks culture. The presence of DREB1A gene in the genomic DNA of regenerated plants was detected by means of PCR analysis.