High hydrostatic pressure (HHP) is an attractive method for food preservation due to resulting improvements in the quality characteristics of foods, in addition to microbial inactivation. This study aimed at improving the nutraceutical potential of red ginseng (Panax ginseng C.A. Meyer). HHP treatment of 600 MPa for 1 min at room temperature in conjunction with conventional steaming and drying processes during red ginseng manufacture significantly (P<0.05) increased the total phenolic compounds (from 1.13 to 1.37 mg maltol equivalent/g of red ginseng), particularly maltol (4.38 to 12.61 mg/100 g of red ginseng). Comparison of HHP-red ginseng with conventional red ginseng and white ginseng showed that HHP-red ginseng had a stronger ability to scavenge 1,1-diphenyl-2-picrylhydrazyl, hydroxyl, and nitric oxide radicals. The ferrous ion chelating and superoxide dismutase activities of HHP-red ginseng were also improved. HHP-red ginseng exhibited a stronger inhibition of rat liver microsomal lipid peroxidation than normal red ginseng. The application of HHP in red ginseng processing is a promising technique to enhance availability of phenolic compounds and nutraceutical characteristics.