Two new ent-kaurane diterpene derivatives, sculponeatins N (1) and O (2), and a new A-ring contracted oleanane triterpenoid, sculponeatic acid (5), were isolated from the plant Isodon sculponeata. Their structures were elucidated on the basis of extensive spectroscopic analysis. This is the first report of natural occurrence of an A-ring contracted oleanane triterpenoid.