Sesquiterpenoids elaborated by Penicillium roqueforti PR Toxin (PRT), eremofortin A, B, C, D (EA, EB, EC, ED), have been studied by 1H NMR and 13C NMR. The structure of a new metabolite eremofortin E (EE) has been established by X-ray diffraction. The absolute stereochemistry of all metabolites has been determined by comparison with the absolute configuration of PRT (determined by X-ray anomalus dispersion) using rotatory dispersion and circular dichroism curves. The sesquiterpenoids of P. roqueforti belong to the eremophilane series with the unusual 7x side chain.