Abstract A new diterpeneacid, methyl-ent-7-α-hydroxypimara-8,15-dien-19-oate, isolated as its methyl ester, and seven known diterpeneacids were isolated from the stems of Mikaniatriangularis . The C-8 stereochemistry of the methyl-ent-pimara-9(11),15-dien-19-oate previously reported was changed. The proposed structures were based upon spectroscopic data and chemical modifications.