Introduction. The present research evaluated the effect of grape skin powder extract addition on functional and physicochemical properties of marshmallow. Materials and methods. To assess the effect of grape skin on marshmallow quality, alcoholic grape skin extracts (GSE) were prepared and introduced in different amounts in marshmallow recipes. The functional properties of marshmallows were estimated by determining the total polyphenol content and antioxidant activity. The microbiological stability of the product was assessed by using agar meat broth. Molds proliferation and morphology of cells from single colonies was studied under microscope. Results and discussion. The effects of grape skin extract (GSE) on marshmallow quality were evaluated. The marshmallow physicochemical properties in terms moisture and sugar content were affected by GSE incorporation. A directly proportional relationship was observed between the addition of GSE and the moisture content of the marshmallow samples, registering an increase from 15.02 to 15.58% for the samples with 1% and 3% GSE respectively. The sugar content varied in the limits of 14.05- 14.21%, being higher for the samples with an increased amount h GSE. Total phenolic content of GSE and marshmallow samples with added GSE was determined as 27.39, 5.11 (1% GSE marshmallow), 6.46 (2% GSE marshmallow) and 7.89 (3% GSE marshmallow) mg/g gallic acid (GAE), respectively. Hydrogen peroxide inhibition capacity and DPPH radical scavenging of marshmallows had increased in proportion to rising GSE level. Antioxidant activity of marshmallows containing 3% GSE was found to be higher (35.72%) than others. The addition of GSE significantly affected the marshmallows color parameters, as the amount of grape skin increased, a more intense purple coloration was observed. The marshmallow containing 2% GSE was most appreciated in terms of sensorial properties. The GSE addition had inhibitory effects on mold population during storage, a higher degree of mold growth reduction (p < 0.05) being observed in the sample with 3% GSE after 7 days of storage. Conclusions. The addition of grape skin extract in marshmallow formulation increased the biological value in terms of antioxidant activity and total phenol content, and the consumers acceptancy.