The antimicrobial activity of the ethanol, acetone, ethyl acetate and chloroform extracts from Centaurea persica Boiss., C. polyclada DC. and C. consanguinea DC. (Asteraceae) were investigated by agar-well diffusion assay. All of the extracts exhibited an antimicrobial effect against most of the bacteria and all of the yeasts tested. The plant extracts were also screened for radical scavenging potential using a 1,1-diphenyl-2-picryl-hydrazyl (DPPH) in vitro model system for antioxidant activity. Ethyl acetate extracts showed the most significant inhibitory activity. Therefore, the minimal inhibitory concentration (MIC) of only ethyl acetate extracts of the samples was determined and C. consanguinea showed the highest antimicrobial effect. However, the ethanol extract of C. polyclada at 0.5 mg/ml, concentration displayed the highest antioxidant activity. This activity was followed by ethanol extracts of. C. persica, ethyl acetate extracts of C. polclada, C. persica and C. consanguinea respectively.