Abstract:Transformed hairy root cultures of Fagopyrum cymosum (Trey.) Meisn. have been established by infecting petioles of shoots cultured in vitro with Agrobacterium rhizogenes. These hairy root cultures grew vigorously in MS hormone-free medium. They showed a 1861-fold increase in fresh weight with in 25 days, and grew faster than cell cultures of F. cymosum (only increased 26.7-fold with in the same days). The cultures were shon to synthesis dimeric procyanidin up to 4.5% (dry wt.) approximating the level of original plant. The growth rates of hairy root cultures up to 149.3 mg dry w-t/L/day in large culture vessels (3 L) and dimeric procyanidin (3.58%, dry wt.) were detected.