abstract essential oils from the whole aerial parts of pimpinella barbata (at vegetative stage), stem/leaf, inflorescence (flowering stage), and unripe and ripe seeds (seeding stages) were isolated individually by hydrodistillation. the oil yields of the aerial parts, stem/leaf, inflorescence, and unripe and ripe seeds oils were 0.67%, 0.42%, 1.29%, 2.05% and 1.71% w/w, respectively. the oils of p. barbata were analyzed by gc and gc/ms. limonene was the major constituent in all of oils (14.9%, 24.3%, 46.9%, 45.3% and 63.6%, respectively). pregeijerene (32.7% in aerial parts oil), -muurolene (28.2% in stem/leaf oil) and methyl eugenol (18.7% in unripe seed oil) were the other major constituents. the antimicrobial activity of the oils was determined by use of the disk diffusion method against gram-positive bacteria (bacillus subtilis, bacillus cereus, micrococcus luteus and staphylococcus aureus) and gram-negative bacteria (yersinia entrocolitica, klebsiella pneumonia and escherichia coli) and yeast (candida albicans). results showed no significant antimicrobial activity in essential oil of p. barbata. key word index: pimpinella barbata apiaceaeessential oil compositionlimonenepregeijerenemethyl eugenol-muuroleneelemicin(e)-foeniculinantimicrobial activity