To improve genetic transformation of Brassica napus winter cultivar 'Youngsan', factors influencing shoot regeneration and transformation from cotyledonary petioles were investigated. Shoot induction was enhanced in the combination of 0.5 mg/L NAA and 2~4 mg/L kinetin. Silver nitrate was essential for successful shoot regeneration, ranging from 5 to 9 mg/L. The addition of GA 3 promoted plant regeneration. Among the tested Agrobacterium strains, co-cultivation times, and antibiotic selection regimes, choice of appropriate Agrobacterium strain was the most critical factor for efficient transformation of B. napus cv. 'Youngsan'. The EHA105 succinamopine strain was the most efficient and the maximum transformation efficiency was 26.8%. Transgenic shoots were selected on 10 mg/L phosphinothricin (PPT) containing media. The transgenic plants expressing bar and gus genes were resistant for commercial herbicide "Basta" and stained with X-Gluc. Southern blot hybridization indicated that the presence of one to three gus gene copies per genome and inheritance of the gus gene into the T 1 generation.