The essential oils of Bupleurum heldreichii Boiss. & Bal., Bupleurum sulphureum Boiss. & Bal., Bupleurum turcicum Snogerup, and Bupleurum lycaonicum Snogerup flowers, fruits and roots were obtained using hydrodistillation and microdistillation techniques and their chemical compositions were analyzed by GC and GC/MS systems, simultaneously. The antibacterial activity of the oils which obtained by hydrodistillation was assessed with micro-dilution assays. The main components of B. heldreichii were germacrene D (% 47.5-48.4) in flowers and fruits, and hexadecanoic acid (% 46.2) in roots. The main components of B. sulphureum found undecane (% 14.0-20.2) in flowers and fruits, and calarene (% 26.9) in roots. The main components of B. turcicum were heptanal (% 33.2-23.5) in flowers and fruits, and pentacosane (% 9.0) in roots. The main components of B. lycaonicum were tridecane (% 14.9-37.3) in flowers and roots, spathulenol (% 14.4) in fruits. The essential oils of B. heldreichii, B. sulphureum, B. turcicum obtained from flowers and fruits, B. lycaonicum from fruits used in the study did not have any effect against bacteria. The MIC values of essential oils of the roots for the bacterial strains tested, which were sensitive to the essential oils of roots of B. heldreichii, B. sulphureum and B. turcicum were in the ratio of 2 mg/ml. This investigation showed that the antibacterial activity of B. heldreichii, B. sulphureum and B. turcicum was attributed to the essential oil of roots, thus they can be a potential medicinal resource.