Trichoderma atroviridae UB-LMA is an endophytic fungus isolated from Taxus baccata trees. Liquid-state fermentation coupled to in situ solid phase extraction (SPE) was applied, and four compounds were discovered. Compounds 2–4 belong to the harziane tetracyclic diterpene family. Bicylic compound 1 may represent the biosynthetic precursor of this scarce family of compounds.