In this study, essential oils of thyme (Origanum vulgare), St. John's Wort (Hypericum perforatum), rosemary (Rosmarinus officinalis), ginger (Zingiber officinale), clove (Eugenia caryophyllata), peppermint (Menta piperita), lavandula (Lavandula hybrida) and black cumin (Nigella sativa) were screened for its chemical composition and in vitro antibacterial activity against Vagococcus salmoninarum. The composition of oils were analysed using GC/MS. Antibacterial effects of essential oils against V. salmoninarum were detected by agar diffusion and tube dilution assays. Thyme (125 mu L ml(-1) MIC) and clove (500 mu L ml(-1) MIC) essential oils were shown to possess strong antibacterial activity against V. salmoninarum. The main components of effective essential oils were carvacrol (63.57 %) and eugenol (85.99 %), respectively. As a result, these two plant species that tested against V. salmoninarum which is causative agent of vagococcosis can be used as an antibacterial agent. For this purpose, in vivo antibacterial activities against vagococcosis of thyme and clove essential oils should be explored in the further studies.