Abstract The chemical composition of the leaf oil of Koanophyllon villosum (Sw.) King et Robins. was studied by GC and GC/MS. Ninety-seven compounds of the oil were identifi ed of which β-caryophyllene (17.0%), caryophyllene oxide (14.1%) and β-pinene (11.3%) were the major components. Key Word Index: Koanophyllon villosum Asteraceaeessential oil compositionβ-caryophyllenecaryophyllene oxideβ-pinene