Further investigation on the leaves of Isodon sculponeatus afforded two new ent-kaurane diterpenoids, sculponeatins J and K. Their structures were elucidated on the basis of their spectral properties, as well as X-ray crystallographic analysis. The cytotoxicities of these two new compounds against human tumor cells K562 and T24 were also tested, andsculponeatin Jshowed significant inhibitory effects with IC50 values less than 1.0 μg/mL.