The terpenic constituents of the leaf-oil of Chamaecyparis taiwanensis MASAM. were examined and 11 monoterpenes, 19 sesquiterpenes, and a diterpene have been identified. On the basis of the present results, the identity of "chamene" and "sesquichamene", both of which have been isolated earlier, with ocimene and thujopsene, respectively, is suggested. The biogenetic significance of the sesquiterpenic constituents of this also discussed.