The aim of the study was to determine the extent of changes in the content of bioactive substances in lingonberry fruit following cold storage, freezing and lyophilisation. In the paper therapeutic properties of lingonberry fruits were presented, and all present in the fruits phenolic compounds were discussed, especially phenolic acids and anthocyanins. The effect of selected technological operations (freezing and lyophilisation)on the content of phenolic compounds in the fruit was described. The antioxidative activity of phenolic compounds present in fruits and juice was also analysed.The results of the study indicate that lyophilisation had a negative impact on the level of all phenolic compounds in lingonberry fruits. During this operation the total content of phenolic compounds decreased for about 37%.At the same time phenolic acids concentration was decreased by 20%. The greatest change was observed in anthocyanins concentration, in lyophilised fruits anthocyanins concentration decreased by as much for about 97%. Such a significant degradation of polyphenolic compounds caused a substantial (36%) decrease in antioxidant activity