Olive pomace is a by-product that remains in large amounts after olive oil production. It is rich in polyphenols, compounds known to have antioxidant activity. In this research, the aim was to examine the stability of polyphenols after exposure to experimental in vitro conditions simulating gastric and intestinal digestion. Apart from the native sample, stability was also tested for samples encapsulated with different types and concentrations of cyclodextrins, which were used in extract formulation due to poor organoleptic properties of the native sample. The amount of bioavailable polyphenols in a single sample was determined by the method of dialyzability. After the analysis, values of the total amount of bioavailable and bioaccessible polyphenols (Folin-Ciocalteu) and the antioxidant activity of gastric digest, bioavailable and bioaccesible fractions for each sample (TEAC) were obtained. Samples with cyclodextrins show a slightly higher gastric stability and bioavailability of antioxidants and phenolic compounds. The presence of cyclodextrin results in a reduction of the dialysability of polyphenols and antioxidants, i.e. by reducing the amount of bioaccessible fraction and potentially lower bioactivity in vivo. Taking into account all observed parameters, the best properties are seen in the sample of olive pomace extract encapsulated with randomly methylated β-CD. For making further conclusions, it is necessary to examine the antioxidant efficacy in Caco-2 cell model and in vivo.