Cranberries fruits like other fresh products lose their basic in particular bioactive components with the course of time and therefore there is a need of their immediate fixation. Drying and freezing are the most commonly used methods of extending the shelf life in the processing of these fruits. The aim of the study was to investigate the effect of thermal processing on the content of biologically active compounds in cranberry (Vaccinium macrocarpon) fruits. Samples of fresh fruits were frozen (-20ºC) and dried in various temperature condition (59 and 65ºC). Moreover, for comparison market cranberry was used. In the fresh and processed samples of cranberry, the content of vitamin C (Tillmans), total phenolic compounds (Folin-Ciocalteau) and antioxidant activity (FRAP) as well as titratable acidity and anthocyanins were determined. Fresh fruits were characterized by the highest level of all tested parameters. Freezing causes the least possible loss of valuable ingredients. Significant losses of biologically active components in convective dried fruits were temperature-dependent but they were more abundant in antioxidant components than sweetened dried cranberry available in market.