Medicinal Limoniastrum guyonianum (Plumbaginaceae) growing in Tunisia was studied for the first time for volatiles from leaves, flowers, seeds and roots. The chemical analysis of the essential oil obtained from different organs was performed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectroscopy (GC-MS). In roots and leaves oils, monoterpenes were found in almost equal level (22.56 and 26.21%, respectively). (3Z) hex-3-enylmethanoate was detected as the chemotype in roots, while furfural (14.63%), methyl-2,4-dimethylbenzoate (14.70%) and 3-phenylprop-2-enylpentanoate (15.05%) were the most abundant constituents from seeds, leaves and flowers, respectively. Furthermore, antibacterial effects of the indicated oils were evaluated against five sensitive bacteria: Escherichia coli ATCC 35218, Pseudomonas aeruginosaATCC 27853, Staphylococcus epidermidis NCIMB 8853, Staphylococcus aureus ATCC 29213 and Micrococcus luteus NCIMB 8166 using both disc diffusion and dilution methods.