Quercetin which has a versatile health benefit was extracted from widely consumed sumac fruits by ethanol-modified supercritical CO2. Analysis of quercetin was performed via high pressure liquid chromatography (HPLC). The effects of temperature, pressure and ethanol content on the amount of quercetin were examined using Central Composite Design (CCD). The extractions were carried out at 40-70(omicron)C temperature, 150-250 bar pressure, and 2-6 wt% ethanol content. It was predicted that the maximum quercetin was obtained as 2196 mu g/100 g sumac at 40(omicron)C, 250 bar, and 6% ethanol content.