The monotypic Zhumeria majdae Rech.F. & Wendelbo was recently described as the first member of new genus Zhumeria (Lamiaceae). In Iranian folk medicine, the leaves of plant were used for antiseptic properties. The antimicrobial activity of Zhumeria majdae essential oil was evaluated against a panel of microorganisms including gram negative, gram positive, yeast and fungi using disc diffusion method and micro broth dilution assay. Generally, the oil exhibited similar levels of antimicrobial activity against different microorganisms but some microorganisms appear to be more sensitive. In particular, oil showed significant power against Klebsiella pneumoniae followed by Staphylococcus aureus, Staphylococcus saprophyticus, Vibrio cholera, Staphylococcus epidermidis and Bacillus cereus. Klebsiella pneumoniae with MIC and MBC values 0.5, 1 μl ml -1 was the most sensitive among the tested microorganisms. The oil showed bactericidal activity against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Enterobacter aerugenes. The oil showed inhibitory effect against Bacillus subtilis, Proteus vulgaris, Aspergillus flavus and Aspergillus niger. Salmonella typhi and Pseudomonas aeruginosa among Gram negative bacteria and Bacillus subtilis among Gram positive ones and Aspergillus niger among fungi and yeast were the most resistant to the essential oil.