The four Australian members of the genus Uromyrtus have been examined for their essential oils. U. australis A. J. Scott gave an oil in 0.12% yield (all yields are quoted on a fresh weight basis) in which sesquiterpenes accounted for over 95% of the oil. The principal components were p-caryophyllene (21%) and y-, a- and peudesmol (13, 9 and 11% respectively). Uromyrtus metrosideros (F. M. Bailey) A. J. Scott gave an oil in 0.15-0.3% yield of which over 50% were monoterpenes. The principal components were a-pinene (13-20%) and p-pinene (33-42%). Other components of significance were a-terpineol (3-7%) and spathulenol (9-15%). Uromyrtus sp. (Tinaroo Range G. P. Guymer 2034) produced an oil in 0.1-0.2% yield which was basically devoid of monoterpenes. The major components were bicyclogermacrene (14-23%), globulol (9-12%), viridiflorol (5-7%) and spathulenol (3-4%). Uromyrtus sp. (McPherson Range G. P. Guymer 2000) gave an oil in 0.4-0.8% yield which contained a significant proportion of monoterpenes. The principal components were terpinen-4-ol (8-13%) and a-pinene (3-10%).