Four new sesquiterpenoids, namely 12-hydroxy-3-oxodrimenol (1), 11-hydroxyacetoxydrim-7-en-3β-ol (2), 2,6-dimethyl-7,10-epoxy-10-hydroxymethyldodeca-2,11-dien-6-ol (3), and 7,10-epoxy-2,6,10-trimethyldodeca-2,11-diene-4,6-diol (4), along with fourteen known compounds, were isolated from the cultures of Phellinidium sulphurascens. The structures of compounds 1-4 were established on the basis of extensive spectroscopic analysis. All of them were evaluated for their cytotoxic activities.