Tortuosenes A and B (1 and 2), possessing new diterpenoid molecular structures, were isolated from the Formosan soft coral Sarcophyton tortuosum along with a known cembrane, emblide (3). The structures of 1 and 2 were established by extensive spectroscopic analysis, and the absolute configuration of 1 was determined by TDDFT ECD calculations. Tortuosene A was found to display significant inhibitory effects on the generation of the superoxide anion in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced neutrophils.