To determine the amounts of flavonoids accumulated in the buds of single-styled hawthorn (Crataegus monogyna Jacq.); and to establish the possibility of usage of hawthorn buds in pharmacy practice. Different examples of hawthorn buds collected in 2001, 2002 and 2003 from some Lithuanian regions: Akmene (V1, V2, V3), Kedainiai (S1, S2, S3), Klaipeda (M1), Lazdijai (D1, D2, D3) and Vilnius (VL1, VL2) from branches of lower storey. Examples were extracted with ethanol and flavonoids were measured by spectroscopic method and by high performance liquid chromatography. From 0.72 to 1.89% of flavonoids are found in the hawthorn buds. The dominating flavonoid is vitexin-2-O-rhamnosid (6.72-10.91 milligrams in one gram of dried crude drug). Other flavonoids are: vitexin: 0.88-6.53 milligrams/gram, hyperosid: 0.85-2.70 milligrams/gram, rutin: 0.72-2.10 milligrams/gram and quercitrin: 0.82-1.01 milligrams/gram. The marks of phytochemical compounds of Lithuanian single-styled hawthorn buds corroborated the theory of possibility to use hawthorn buds as pharmaceutical crude drug and form sufficient ground for planning phytochemical and pharmacological researches of new hawthorn crude drug.