The volatile constituents of Prangos pabularia Lindl. fruits (Umbelliferae) were obtained by hydrodistillation (HD) and microdistillation (MD) techniques, and then analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) methods. One hundred and twenty-eight compounds have been characterized representing 90.5% of hydrodistilled oil (HDO). In the microdistilled oil (MDO), 115 compounds constituting 93.0% of the oil were detected. alpha-Humulene (16.6% and 15.5%), bicyclogermacrene (16.1% and 7.9%), spathulenol (10.6% and 5.7%), germacrene D (5.7% and 2.9%) and alpha-pinene (4.2% and 23.9%) were found to be the major constituents of HDO and MDO, respectively. Antimicrobial activity of the oil was tested via microdilution broth technique. Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhimurium, Staphylococcus epidermidis, Methicillin-resistant Staphylococcus aureus, and Candida albicans were used as the test microorganisms. (c) 2007 SAAB. Published by Elsevier B.V. All rights reserved.