Edible fruits are known as source of bioactive compounds, however, growing interest in the use of plant byproducts has been observed in last few years. The objective of study was to compare the chemical composition, fatty acid profile, content of bioactive compounds, including the HPLC analysis of anthocyanins and antioxidant activity of sweet cherry fruit, petioles and leaves of the following cultivars: Burlat, Kordia and Regina. In the fruit, the major fatty acid was oleic acid, and in the petioles—palmitic acid and in the leaves—the γ-linolenic acid. The petioles were characterized by the highest antioxidant activity and content of polyphenols, whereas the anthocyanins were detected only in fruit. Two anthocyanins were identified: cyanidin 3-glucoside and cyanidin 3-rutinoside. Fruit of cultivar Kordia as well as petioles and leaves of cultivars Burlat and Regina had the highest antioxidant activity. There is a need for further research (especially in vivo studies). This knowledge can be used to create a new functional food and to better use of byproducts of sweet cherry production.