Several in vitro methods have been conducted in order to investigate the antioxidant activities of ethanol extract from Rehmannia glutinosa. Both the total phenolic and flavonoid component were expressed as the equivalent of positive control with the values of 1432.3±16.2 mg TAE/100 g and 97.6±14.1 mg QE/100 g, respectively. In addition, the antioxidant activity with an IC50 of 469.87±12.42 μg/g was measured via the DPPH scavenging activity. The study also showed that Rehmannia glutinosa ethanol extract exhibited antioxidant activities on metal-chelating, reducing power, total antioxidant activity assay.