Abstract: Herbal medicine represents one of the most important fields of traditional medicine all over the world. Plants produce certain bioactive compounds which are naturally toxic to microorganisms and so have been investigated as therapeutic agents. The present study was carried out so as to evaluate in vitro the antimicrobial effect of essential oils of two aromatic medicinal plants namely, Lemongrass and Eucalyptus. The in vitro evaluation was done for individual oils and combination of the two oils in 1:1 ratio against four bacterial pathogens of nosocomial infections namely Staphylococcus aureus, Bacillus subtilis, Escherishia coli and Klebsiella pneumoniae. The combination formula was used with two assumptions one that individual oil may show ineffectiveness if used repeatedly as seen in antibiotics and second the combined formulation may show wider range of antimicrobial activity. The antimicrobial activity of the plant essential oils was screened using Agar well diffusion method and the minimal inhibitory concentration (MIC) of the essential oils was determined by Broth assay method. The study showed promising results for the use of Lemongrass and Eucalyptus as antimicrobial agents.