The fruit of black chokeberry (Aronia melanocarpa (Michx.) Elliott) is valuable raw material for food and pharmaceutical industries due to the content of anthocyanins, but also other components. The aim of this study was to estimate the content of dry matter, reducing sugars, vitamin C, anthocyanins and the antioxidant potential in black chokeberry fruits depending on the age of plants and the time of fruit harvest. Material for the study was collected in 2011 and 2012 from 6–7, 11–12 and 16–17-year-old plants. Fruits for analyses were harvested on 10–12 August, 29 August – 1 September, 11–13 September, 26–27 September, 11–14 October, 25–27 October. Fruits from the oldest plants contained 16–18% less anthocyanins and 8% less vitamin C, but 2.7 percentage points more dry matter than the fruits from younger plants. On the 29 August–1 September fruits achieved the maximum content of reducing sugars, vitamin C and anthocyanins, 13.7, 8.2 and 715.5 mg 100 g^-1, respectively. The content of reducing sugars and anthocyanins stayed unchanged until the end of October, and the content of vitamin C decreased considerably. Antioxidative potential (DPPH) ranged from 77.0 to 85.2% inhibition and it did not depend on the age of harvest time of fruits. The most valuable chokeberry fruits were obtained from plants up to 12 years of age, harvested between 29 August and 13 September.

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