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), Î³-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 eugenolÎ³-muuroleneelemicin(E)-foeniculinantimicrobial activity