A preliminary analysis performed on a set of Antarctic bacteria belonging to the genera _Pseudoalteromonas_, _Psychrobacter_, and _Shewanella_ has revealed that the synthesis of VOCs is constitutive, in that it is not induced by the presence of target strains [15]. Given the fact that Antarctic bacteria previously analysed by [PERSON] et al. [14] did not affect the growth of other classical bacterial human pathogens at all, it has been strongly suggested that the Bcc strains possess a metabolic trait that is sensitive to one or more VOCs produced by Antarctic bacteria, so these compounds might represent new antimicrobial compounds able to face CF patient infections [17]. The finding that secondary metabolites synthesized by microorganisms can inhibit the growth of pathogenic bacteria has been confirmed by recent data regarding strains isolated from different compartments of medicinal plants [18; 19; 20]. The use of medicinal and aromatic plants has a very ancient history in the prevention and treatment of mental and physical illnesses, also due to the production of essential oils (EOs). Synthesized as secondary metabolites, EOs appear as mixtures of volatile compounds. They are mainly involved in the protection of their host from phytopathogens and herbivores, and in the attraction of insect pollinators [21]. The antimicrobial activity of various EOs has been demonstrated, and nowadays, more efforts need to be addressed to the discovery of alternative bioactive molecules able to inhibit MDR human pathogens. In this scenario, major constituents of aromatic plant EOs can potentially be employed as antibacterial and antifungal agents [22]. To better exploit the pharmacological potential of medicinal plants and their EOs, it is essential to consider them as a dynamic and complex system; beside abiotic factors, their chemical composition also depends on the interactions between the plant and its endophytic microbiota [23]. Bacterial endophytes are microorganisms that inhabit the internal tissues of a plant without causing any sign of infection. The relationship between medicinal aromatic plants and their microbiota seems to rely on the production of secondary metabolites by both the plant and the bacteria: the plant selects the microorganisms that best adapt to its inner compartments, while the endophytes can modify these microenvironments influencing the plant secondary metabolism [23; 24; 25]. The endophytic community might also be directly responsible for the production of VOCs [26], but it is still not clear whether those volatile metabolites can actually contribute to the composition of the aroma profile of aromatic plants' EOs. Considering their potential biotechnological applications as aroma producers or drug sources, endophytic bacterial strains have been isolated from _Origanum vulgare_ ssp. _vulgare_ aerial parts, as described in [PERSON] et al. [27]. The endophytes were tested for their antibacterial activity against Bcc strains via cross-streaking tests; eight of them showed a relevant growth inhibitory ability, probably due to the production of antibacterial bioactive compounds that diffused through the agar culture medium [27]. Little is known about the chemical nature of the produced metabolites, and one may ask if the antibacterial effect can also be attributed to the production of bacterial VOCs. In the present study, the eight endophytic strains were characterized by means of both volatile-mediated inhibitory activity assay and solid phase micro extraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) in order to investigate their ability to produce VOCs able to antagonize the growth of opportunistic human pathogenic Bcc strains. Moreover, the obtained VOC profiles were compared with the aroma profile of the EO extracted from the same _O. vulgare_ plants from which the endophytes were isolated [27], in order to check whether any bacterial compound might contribute to the EO composition.