In searching for naturally occurring anti-inflammatory agents, three new abietane-type diterpenoids, named 16-hydroxylambertic acid (1), 7-oxo-18-hydroxyferruginol (2), and 5 alpha, 12-dihydroxy-6-oxa-abieta-8,11,13-trien-7one (3), were isolated from the seeds of Podocarpus nagi, together with three known compounds. The structures of the new compounds were elucidated by extensive analysis of NMR and HR-ESIMS data. All the new compounds were tested for nitric oxide (NO) inhibitory activities on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Compound 1 significantly inhibited NO production with IC50 value of 5.38 +/- 0.17 mu M, and suppressed inducible NO synthase (iNOS) expression in a dose-dependent manner, which were mediated through inhibiting the mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-kappa B) activation.