Abstract The essential oils from the leaves and stems of Ferula szowitsiana DC. (Umbelliferae) were separately obtained by hydrodistillation and then analyzed by GC and GC/MS methods. The oil yields were 0.4% and 0.05%, respectively. One-hundred and sixty-two compounds representing 99.5% and 99 compounds representing 94.4% were identified in the leaf oil and stem oil, respectively, with Î²-eudesmol (32.0% and 29.5%, resp.), Î±-eudesmol (18.2% and 16.6%, resp.) and Î±-pinene (8.6% and 6.4%, resp.) as the major constituents. Antimicrobial activity of the leaf oil was tested via in-vitro 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.