From the woods of Excoecaria agallocha, a new isopimarane-type diterpene, 3alpha,11beta-dihydroxy-ent-isopimara-8(14),15-dien-2-one and a new natural atisane-type diterpene, 16beta-hydroxy-ent-atisan-3-one were isolated together with three known compounds, ribenone, ent-labda-8(17),13E-diene-3beta,15-diol, and ent-3beta-hydroxybeyer-15-ene-2,12-dione. Their structures were determined by spectral data and x-ray crystallography evidence.