This study was performed to assess the impact of supplementation of red grape pomace and tomato pomace extracts (200, 400, and 600 ppm) on the chemical composition, sensory properties, and oxidative stability of sour cream substitutes kept at 5-8 °C for 4 weeks. Red grape pomace and tomato pomace extracts showed high total phenolic contents (990.60 and 470.20 mg/100g), total flavonoids contains (120.60 and 76.20 mg/100g) and radical scavenging activity (92.40 and 85.30 %), respectively. The supplementation of sour cream with extracts at different concentrations did not appreciably change the levels of fat and total solids, but increased total volatile fatty acids, and slightly decreased the acidity. Treatments with 400 and 600 ppm of grape pomace extract had decreased peroxide, acid, and TBA levels and higher oxidative stability index (Rancimat) at the time of storage at 5°C than other treatments. The study demonstrated that grape pomace and tomato pomace extracts at concentrations of 400 or 600 ppm could be used as natural antioxidants for sour cream analogue. Further studies are recommended to investigate the application of these extracts in other dairy products.