Plants extracts has been used in traditional medicine for many years. The use of them has the least side effects in comprison to the synthetic drugs. The aim of this study was investigation and comparision of biological active components of Quercus persica and Quercus ilex. Sampling was done from Quercus persica and Quercus ilex stands. The antibacterial activity was assayed against Psuodomonas aeruginosa, Klebsiella pneumonia and Eschechia coli in aqueous, ethanol, acetone and hexane extracts of leaves by means of agar diffusion method in nutrient agaar. Bacteria were incubated at 37°C and the inhibition zone was measured. Aquaous and hexane extracts did not show antibacterial activity but ethanol and acetone extracts of Quercus persica and acetone extracts of Quercus ilex had antibacterial activity. The inhibition zone for Klebsiella pneumonia Eschechia coli and Psuodomonas aeruginosa of ethanol and acetone extract of Quercus persica were 11, 10, and 14 mm and 8.5, 12 and 15 mm, respectively. The inhibition zone for acetone extract of Quercus ilex against Klebsiella pneumonia Eschechia coli and Psuodomonas aeruginosa were 10, 10 and 18 mm, respectively. Results indicate that some species such as Quercus that seem to be useless have many biologically active components. Comparison between two species shows that endemic species (Quercus persica) are more active than nonendemic species (Quercus ilex).