Abstract: Propolis is a substance made by the honeybee that provides protection against harmful bacteria, viruses and fungi. The present study was designed to investigate the chemical composition and antimicrobial activity of Iranian propolis. One hundred forty compounds were identified by gas chromatography. Important chemical compositions in these propolises are: Flavonoids, Esters, Aliphatic acids, Aromatic acids, Sugars and sugar alcohols. All samples propolis ethanol extract Practice killed gram-positive, gram-negative bacteria and fungi with the highest antimicrobial activity against gram-positive bacteria.