Santalum album and S. spicatum are grown chiefly in southern India and Western Australia respectively. The essential oils (especially from Santalum album) are highly prized for their organoleptic and medicinal properties, and on account of its importance in perfumery and medicine, sandalwood oil has been investigated by several workers [1]. The main constituents of the sandalwood oils have been found to be α and β-santalol (ca 90%) which are responsible for the general odour of the oils. In undertaking an analysis of both essential oils, our aim was to identify potentially important perfumery compounds present in the more volatile fractions. Petrol extraction of both East Indian and Australian sandalwoods afforded ca 7% of essential oil. Both essential oils gave a 'hydrocarbon fraction' (see Experimental) representing ca 6% of the total oil. A GLC analysis of the 'hydrocarbon fraction' from Australian sandalwood on 5% carbowax, temperature programmed 80-200°C, showed that it contained about ten components, of which α (1), β (2), and epi-β-santalene represented ca 21, 20 and 11% respectively of the total 'hydrocarbon' content, identified initially by mass spectral data comparison with literature data [3]. The hydrocarbon fraction from East Indian sandalwood under the same GLC conditions was shown, however, to consist of about nine components of which α, β, and epi-β-santalene were ca 23, 36 and 21% of the total respectively. Both hydrocarbon fractions were subjected to preparative GLC on a 15% carbowax column, temperature programmed 80-100°C. The components shown in Table I were isolated (unless indicated otherwise) and each gave a single peak when subjected to GLC analysis on two columns (5% carbowax and 5% OVT). All the compounds, where shown, were identified from their MS, NMR and IR spectral data by comparison with the literature [2, 3]. Several other trace components in the 'hydrocarbon fraction' from East Indian sandalwood oil were detected and one was tentatively identified as β-farnesene from its mass spectrum [4]. Although the chemical compositions of Australian and East Indian sandalwood oils are known to be different, the difference (Table 1) in santalene content has not been reported. The presence of α and β-curcumene (3) and (4) in sandalwood oil tends to support the proposed biosynthetic pathway for the formation of α and β-santalene (1) and (2) from farnesyl pyrophosphate [5]. Dendrolasin is a new odour constituent of sandalwood oil (sweet lemon grass odour) and to the authors' knowledge, this is the first report of the presence of both dendrolasin and β-farnesene in sandalwood oil.