Essential oil extracted from aerial parts of Artemisia nilagirica was analysed by gas chromatography-mass spectroscopy. Forty-three constituents amounting to 98.16% of the total essential oil contents were identified. The essential oil contained approximately 79.91% monoterpenoids and 18.25% sesquiterpenoids. α-Thujone (36.35%), β-thujone (9.37%), germacrene D (6.32%), 4-terpineol (6.31%), β-caryophyllene (5.43%), camphene (5.47%) and borneol (4.12%) were identified as the major constituents. The essential oil exhibited significant antifungal activity against Rhizoctonia solani (ED(50), 85.75 mg L(-1)), Sclerotium rolfsii (ED(50), 87.63 mg L(-1)) and Macrophomina phaseolina (ED(50), 93.23 mg L(-1)). This study indicated that A. nilagirica essential oil can be used to control phytopathogenic fungi infesting agricultural crops and commodities.