Repeated chromatography of the n-hexane-soluble fraction of the MeOH extract of the rhizomes of Zingiber zerumbet led to the isolation of two isomers of 6-methoxy-2E,9E-humula-dien-8-one (1 and 2) and stigmast-4-en-3-one. The structures of 1 and 2 were determined by spectroscopic methods including 10 and 2D-NMR elucidated by analysis of spectroscopic data as well as by comparison with published values. This is the first report on the isolation of compounds 1 and 2 from the nature. Stigmast-4-en-3-one was first isolated from this plant.