chemical composition and antibacterial activity of the essential oils isolated from fruits and leaves of peucedanum austriacum (jacq.) w.d.j. koch were determined in order to define their medical potential. an analysis of leaf and fruit essential oils by gas chromatography (gc) and gc/mass spectrometry (gc/ms) resulted in identification of 141 different components, representing 93.6% and 96.1% of the total oils. the most abundant class of compounds in fruit essential oil was monoterpenoids (64.0%) and in the leaf essential oil sesquiterpenoids (82.0%). the major contributors of fruit essential oil were -phellandrene (45.2%) and -pinene (10.1%). the major constituents of leaf essential oil were caryophyllene oxide (23.1%), germacrene d (12.2%) and (e)-caryophyllene (10.2%). minimal inhibitory (mic) and minimal bactericidal concentrations (mbc) were determined by performing broth microdilution assay. in the antibacterial activity assay, both samples showed moderate activity against bacillus subtilis and staphylococcus aureus with inhibitory effect at 0.625 and 1.25 mg/ml, weak activity against pseudomonas aeruginosa with inhibitory effect at 5.00 mg/ml and no effect on the growth of bacteria escherichia coli and salmonella typhimurium. the results showed that essential oils composition of p. austriacum leaves and fruits differed considerably. tested oils were proved selective antibacterial agents.