Two unusual triterpenoids, (24S)-24-methyl-25,32-cyclo-5alpha-lanosta-9(11)-en-3beta-ol and (24S)-24-methyl-25,32-cyclo-cycloartane-3beta-ol, were isolated from leaves of Pandanus boninensis along with known triterpenoids and lignans. Their structures were established on the basis of spectroscopic methods and X-ray analysis.