The content of the two flavonoids, luteolin and luteoloside, in dandelions was determined by high-performance liquid chromatography. A $Nucleosil^{(R)}100-5C_{18}$ column was used for the determination of luteolin and luteoloside concentrations. The mobile phase was a mixture of acetonitrile and water containing 0.1% formic acid (99.9:0.1, v/v). The gradient elution program was 10% to 23% acetonitrile within 60 min at a flow rate of $1.0mL{cdot}min^{-1}$. The ultraviolet spectra were recorded at 350 nm for the identification of the two flavonoids. The contents of luteolin and luteoloside were highest in T. officinale flowers ($5.817{pm}0.030mg{cdot}g^{-1}$) and in T. coreanum leaves ($6.205{pm}0.087mg{cdot}g^{-1}$), respectively. The total content of luteolin and luteoloside in T. coreanum was about 1.3-2 times higher than that found in T. ohwianum and T. officinale.