Polyphenolic compounds are gradually released from the fruit during the simulated digestion process. The aim of this work was to examine the kinetics of the release of polyphenolic compounds from apples during digestion in the stomach and small intestine. Apple polyphenols were extracted by chemical extraction and enzyme-assisted extraction, and extracts were analyzed using RP-HPLC method (Reversed-Phase High-Performance Liquid Chromatography) to determine the amount of polyphenols before digestion. After that, the simulated digestion of apples in the stomach and small intestine was carried out in vitro, in different time periods, and the samples were analyzed with RP-HPLC method to determine the amount of polyphenols during the digestion. Compounds that have been identified and quantified are commonly found in apples (flavan-3-ols, phenolic acids, dihydrochalcones, flavonols and anthocyanins). The amount of polyphenols during the digestion was lower than the amount naturally found in apples. Polyphenols that were identified after the digestion in the stomach were the same as those identified before the digestion, with additional identification of cryptochlorogenic acid, while procyanidin B1 was not identified. After the digestion in the small intestine certain differences in the occurrence of polyphenols were found. Along with the usual polyphenols, cryptochlorogenic acid, neochlorogenic acid, and an isomer of chlorogenic acid have been identified. Procyanidin B1 and cyanidin-3-galactoside were not identified. These differences were influenced by different pH in different stages of digestion. The amounts of polyphenolic subgroups (ct) released in time (t) were analyzed with nonlinear regression by using modified equations of the first and second order reactions. According to the reaction half-time (t1/2) for the stomach (1.5 – 3.8 min first order reaction, 0.5 – 3.5 min second order reaction) and for the small intestine (0.2 – 5.9 min first order reaction, 0 .8 – 5.2 min second order reaction) half of the total released polyphenols were released in the first few minutes of digestion. The total amounts of polyphenols released at the end of the digestion \((C_{exp})\) correspond to the amounts predicted by the models \((C_{00})\). The modified equations can be used to investigate the kinetics of polyphenol release in the digestive process.