Common buckwheat is a valuable source of the flavonoid rutin. Its in vitro culture was derived from a young seedling plant and the content of flavonoids in the callus culture was compared with their content in an intact plant. The optimal nutrient medium for the cultivation of the in vitro culture and for the production of flavonoids is Murashige and Skoog medium which contains, during the cultivation in the normal light regime, the growth regulators combination of 2,4-D 1 mg/l and kinetin 1 mg/l.