In order to obtain Ti plasmid which may be used in genetic engineering of higher plants, virulent Agrobacterium tumefaciens were isolated from soil with selective medium. For their identification, morphological and cultural characteristics were investigated in parallel with physiological and turnorigenesis test. 14 strains were isolated from various regions in Korea. 3 of them were identified as biotype 1 and the others were so heterogeneous that they are not yet conformed to any biotypes. However, Ti plasmid was isolated from A. tumefaciens KU 14 strain, one of the above mentioned 14 strains.