The essential oil of Thryptomene saxicola is shown to contain α-pinene, 1,8-cineole, γ-terpineol, globulol, O-isobaeckeol and its homologue. The genus Thryptomene is endemic to Australia and consists of ca 25 species [1] most of which are restricted to the south-west and Eremean provinces of Western Australia [2]. Previous work on Thryptomene had been restricted to the detection and isolation of sesquiterpenes. Thus the essential oil of T. kochi has been shown to contain aromadendrene and globulol [3,4]. The presence of the latter in T. australis Endl and T. stenocalyx F.v.M. has also been established [4]. As part of a screening programme of essential oils from Western Australian plants, we had the opportunity of analysing the essential oil of a sample of T. saxicola (A. Cunn.) Schau which from preliminary examination appeared to contain two aromatic compounds. These have been characterized as O-isobaeckeol (1) and its homologue (2).