A new cycloartane saponin along with two known compounds, cimigenol and cimigenol 3-O-beta-D-xyloside, was isolated from the rhizomes of Cimicifuga acerina (Sieb. et Zucc.) Tanaka (Ranunculaceae). The structure of the new compound was elucidated as 3'-O-acetyl cimigenol 3-O-beta-D-xyloside on the basis of chemical and spectral evidence.