A decrease in contents of anthocyanins, total phenolics, chlorogenic acid and antioxidant capacity in different highbush blueberry (Vaccinium corymbosum L.) jams was studied during processing and storage. Jams prepared with sucrose (high-sugar and low-sugar jams), sweeteners (light jam), sweeteners and oligofructose (light jam with oligofructose) were processed with the use of the same parameters. The content of phenolic compounds and antioxidant capacity were determined directly after production and after 2, 4 and 6 months of storage of the jams. Bearing in mind the content of fresh fruit in jams, the processing of berries evoked a reduction in the antioxidant capacity by 13 to 19%. The difference in total phenolics and anthocyanins contents of all blueberry jams was significant. The highest content of phenolic compounds was reported in the high-sugar jam, whereas the lowest one in the product with oligofructose. The HPLC analysis showed changes in blueberry anthocyanins profile during jam processing. Arabinosides were more labile than galactosides and glucosides. In contrast, stability of individual anthocyanins during storage was very similar. The rate of anthocyanins and antioxidant capacity degradation was influenced, to a substantial extent, by temperature and time of storage.