The chemical composition of the rhizome oils of four Malaysian Curcuma species (Curcuma mangga, C. xanthorrhiza, C. aeruginosa and C. domestica) was determined by co-chromatography with authentic samples on two columns of different polarity, GC/MS and linear retention indices. Myrcene (81.4%) was the most abundant component in the oil of C. mangga. The oil of C. xanthorrhiza was made up mainly of sesquiterpenoids of which xanthorrhizol (44.5%) was the major constituent. 1,8-Cineole (23.2%) and curzerenone (28.4%) were the predominant constituents of the oil of C. aeruginosa. The oil of C. domestica contained significant amounts of α-tumerone (45.3%), linalool (14.9%) and β-tumerone (13.5%).