The chemical constituents of Kyllinga brevifolia Rottb. var. leiolepsis Hara (Cyperaceae) were studied. From the chloroform and n-butanol soluble fractions, five compounds were isolated by chromatographic purification process. They were identified as ${eta}-sitostenone$, ergosterol peroxide, ${eta}-sitosterol$, ${eta}-sitosteryl$-3-O-{eta}-D-glucopyanoside and vitexin, respectively. This is the first report of the identification of ${eta}-sitostenone$, ergosterol peroxide from Cyperaceae.