Abstract The essential oils from aerial parts of five Eryngium species of New South Wales have been examined by GC and GC/MS. The oil of Eryngium expansum F. Muell was characterized by a high amount of 7-epi-α-selinene (38.3%), cis-β-guaiene (10.8%), 2,3,6-trimethylbenzaldehyde (8.0%) and (E,E)-α-farnesene (7.3%). The leaf oil of E. pandanifolium Cham. et Schlecht contained bornyl acetate (20.8%), β-selinene (13.8%), α-selinene (11.3%) and α-muurolene (8.0%) as the main compounds, while the fruit oil was characterized by heptanol (11.5%) and β-selinene (9.2%). The principal compounds of E. rostratum Cav. were found to be spathulenol (20.0%) and β-bisabolol (8.6%) in the leaf oil while β-bisabolol (65.3%) was the main component in the fruit oil. β-Caryophyllene (20.3%), germacrene D (19.2%) and α-humulene (8.8%) were found to be the major compounds of E. vesiculosum Labill. Two populations of an undescribed species (E. sp.1, E. sp. 2) of this genus were also studied, the principal compounds being α-pinene (14.5â46.2%), bicyclogermacrene (7.1â16.4%), cubebol (0.6â9.0%) and spathulenol (0.8â8.7%). This is the first report on the essential oil composition of these Australian species.