The chemical composition of Nepata nuda essential oil was hydrodistilled and characterized by gas chromatography-mass spectrometry (GC-MS) and altogether 24 components were detected. The main constituents were trans-caryophyllene (23.9%), isopulegone (12.6%), cis-sabinol (10.1%), and beta-pinene (10.0%). Antimicrobial activity of the oil against Gram-positive and -negative bacteria and fungus, was determined by the disc diffusion assay. The oil showed antibacterial activity against Klebsiella pneumoniae and Salmonella typhi. The antioxidant activity of the essential oil was investigated using 2,2-diphenylpicryl-hydrazyl (DPPH) radical scavenging assay and the -carotene-linoleic acid test. butylated hydroxytoluene (BHT) was employed as a positive control. The essential oil of N. nuda showed weak antioxidant activities. The results suggest that N. nuda essential oil could be a natural antibacterial agent.