The purpose of the master’s thesis was to determine the effect of light-emitting diodes irradiation and/or hot water dipping (HWT) on the chemical composition and CIE colour L*, a*, b* parameters of black currant. Black currant was treated with hot water at 50 °C for 4 min and/or exposed to UV-B (310 nm) and blue LEDs (444 nm) for 21 days at 0,5 °C. Non-treated control was also stored at 0,5 °C for 21 days. The following analyses were carried out before and during treatments: antioxidant potential (AOP) was determined using DPPH˙ radical, content of phenolic compounds with Folin-Ciocalteu assay and total flavonoid content with AlCl3. The fruit colour was measured using Chroma Meter Minolta and the CIE L*, a*, b* system. The results showed a trend of an increase of the AOP, total phenolic and flavonoid content for all treatments during 21-day storage period. Blue light irradiation resulted in the highest increase of AOP, total phenolics and flavonoids as well as changes in colour parameters (L*, a*, b*, C* and h°). Only the samples treated with HWT and illuminated with UV-B differed significantly from non-treated control and non-treated UV-B. HWT showed trend to retard the synthesis of phenols and flavonoids.