The leaf essential oil compositions of four Cinnamomum species from Vietnam were analyzed by gas chromatography (GC) and GCâmass spectrometry (GCâMS). The main compounds of Cinnamomum sericans Hance were the sesquiterpenes spathulenol (14.5%), caryophyllene oxide (9.3%), β-caryophyllene (7.1%) and bicyclocgermacrene (6.0%). The monoterpenes were represented by α-pinene (9.3%) and sabinene (8.0%). However, monoterpenes were the dominant class of compounds in Cinnamomum durifolium Kosterm comprising mainly of Ï-cymene (15.6%), limonene (13.9%) and α-phellandrene (9.2%). Spathulenol (7.4%) among the sesquiterpenoids and benzyl benzoate (6.5%), an aromatic ester were also present. The leaf oil of Cinnamomum magnificum Kosterm was devoid of monoterpene compounds, while the major sesquiterpenes were bicyclogermacrene (33.9%), β-caryophyllene (25.5%), bicycloelemene (7.2%) and caryophyllene oxide (7.5%). β-Caryophyllene (35.9%), caryophyllene oxide (12.6%) and spathulenol (5.2%) were the dominant compounds of Cinnamomum iners Reinw. ex Blume. The low content of (E)-cinnamaldehyde in the Cinnamomum species is typical for majority of species already reported from Vietnam.