First part of this study was to evaluate phenoloxidase activity, phenol content, antioxidant activity and colour of fresh apple juice. Apple juice was obtained from Golden Delicious, Pink Lady and Fuji varieties. The highest phenoloxidase activity had juice from Fuji variety, than Golden Delicious and Pink Lady. The highest phenol content and antioxidant activity had juice from Pink Lady variety, than Fuji and Golden Delicious. During storage phenoloxidase activity decreased and degradation of phenols occurred. The objective of second part of study was to investigate influence of trehalose and sucrose addition (10 %) on phenol content, antioxidant activity and colour in thermally treated apple juice during storage at 4 °C and room temperature. Control sample was apple juice without sugar addition. The highest phenol content had juice from Pink Lady variety, than Fuji and Golden Delicious (828.25, 796.01 and 749.67 mg/L, respectively). During storage, degradation of phenols was higher in samples stored at room temperature. Addition of sugars had high influence on phenol content in comparison to control sample. Samples with addition of sucrose had lower, while samples with addition of trehalose had higher phenol content in contrast to control sample. DPPH and ABTS methods were used for antioxidant activity determination. The lowest antioxidant activity had juice from Pink Lady variety (5.82 and 8.48 μmol TE/100 mL obtained with DPPH and ABTS method). Juice from Fuji and Golden Delicious variety had similar values of antioxidant activity regardless of used method (~7.3 and ~10.2 μmol TE/100 mL obtained with DPPH and ABTS method). During storage, increase of antioxidant activity in all samples occurred.