Abstract:A hairy root system of Cyanotis arachnothea C. B. Clarke has been established from its intact plants, and the root and leaf explants by using a wild strain pRi 15834 of Agrobacterium rhizogenes. The hairy roots grew well on MS hormone free agar medium. Mannopine was charac-terized in the transformed roots by paper electrophoresis and high performance thin layer chromatography. The genomic DNA analysisof the hairy roots was carried out by Southern hybridization and chemiluminescent detection. The rolc bacteria gene existed in the nuclear genome of the roots. This indicated that T-DNA of Ri plasmid was inserted into plant DNA. The hairy root system of C.arachnonda is one of the fewexamples of monocotyledous plants for inducing hairy roots.