Abstract Black chokeberry, Aronia melanocarpa (Michx.) Elliott (Rosaceae), was investigated for its flavonoid content. The flavanone eriodictyol 7- O - β -glucuronide ( 1 ) together with the quercetin derivatives 3- O -(6″- O - β -arabinosyl- β -glucoside) ( 2 ), 3- O -(6″- α -rhamnosyl- β -galactoside) ( 3 ), 3- O -(6″- α -rhamnosyl- β -glucoside) ( 4 ), 3- O - β -galactoside ( 5 ) and 3- O - β -glucoside ( 6 ), were detected in the fruits and flower umbels. The rare compounds 1 – 3 were isolated and structurally elucidated by use of 1D- and 2D-nuclear magnetic resonance experiments together with electrospray mass spectrometry. Compounds 4 – 6 were characterized by co-chromatography and by liquid chromatography-mass spectrometry. The black chokeberries contained >71 mg flavonols per 100 g fresh weight.