The resistance of Staphylococcus aureus, a gram-positive bacterium causing several pathogenic disorders, to antibacterials, is increasing worldwide.To investigate for pant antibacterials effective against S. aureus, 180 methanolic plant extracts of 72 plant families, having ethnopharmacological usage by Iranian Native People, were tested against three isolates of S. aureus in an in vitro bioassay. Seventy-nine plant samples in 41 families exhibited anti-S. aureus activity. Bioactivities were determined by measuring Diameter of inhibition zones. The extracts with the broadest spectra of activity, were used to evaluate Minimum inhibitory concentrations (MIC). The least MICs belonged to Myrtus communis and Terminalia chebula seeds as 0.93 and 0.46 mg ml-1, respectively. The active extracts were well stable in dimethyl sulfoxide: methanol (1:1, v/v) solvent and dried forms at room temperature with no reduction of activity up to 18 months.