ABSTRACT: Essential oils are commonly used to treat minor health problems. In this study the chemical compositions of Lavandula officinalis and Thymus vulgaris were determined by gas chromatography and mass spectrometry. GC/MS analysis of T. vulgaris resulted in thymol as the major oil component where as methyl sulfony exhibited as the most abundant constituent of L. officinalis. The antibacterial activities of these essential oils (Eos) against Five gram negative bacteria, namely Pseudomonas aeruginosa, Salmonella paratyphi (D), Citrobacter, Enterobacter, Escherichia coli and gram positive bacteria Staphylococcus aureus coagulase were investigated. Among the tested plants, Thymus vulgaris showed higher activity against different bacteria, while S.paratyphi and S. aureus were the most resistance bacteria. All the tested plant extracts possessed antimicrobial growth activities with MIC values ranging from 100 to 150µL/mL. The results suggested that due to the potential antimicrobial activities of these essential oils they might be employed in food and pharmaceutical products.