A novel polyhydroxyl sterol (1) along with one known polyhydroxyl sterol (2), and two known monoglycosides, asterosaponin P1 (3) and its desulfated monoglycoside (4), have been isolated from the whole bodies of a common Pacific starfish Asterina pectinifera. The structure of the new polyhydroxyl sterol was determined as 15β,16β-isopropylidenedioxy-5α-cholestane-3β,4β,6α,7α,8,26-hexaol by spectroscopic methods, including FABMS, HR-FABMS, 1D and 2D NMR techniques.