Propolis is a resinous natural hive product derived from plant exudates collected by honey bees. Due to biological and pharmacological activities, it has been extensively used in folk medicine. The present study was designed to measure the antioxidant power of ethanolic extracts of propolis samples from different parts of Iran with “ferric reducing ability of plasma” (FRAP) assay and compare the results with Trolox at concentrations of 100, 1000 and 2000μg/ml. FRAP values of propolis ethanolic extracts were in the range of 31.5±14.6 to 1650±72μM, whereas the values of Trolox ranged from 125.25±9.95 to 3381.64±113.83μM. The FRAP values of Tehran propolis ethanolic extract and Trolox at concentration of 100μg/ml did not show any significant difference (P>0.05). Total flavonoid and polyphenol contents of ethanolic extracts of propolis samples, determined by using aluminum nitrate and Folin–Ciocalteu colorimetric methods, were in the range of 1.22±0.33–7.79±0.39g/100 g and 3.08±0.02–8.46±0.03g/100g crude extract of propolis, respectively. The result of this experiment may show that propolis as a natural source of antioxidant compounds may be of use in prevention of free radical-related diseases.