(+)- and (-)-petromyroxol [(+)-1 and (-)-1, respectively], two novel tetrahydrofuran (THF)-diol fatty acid enantiomers, were isolated from water conditioned with larval sea lamprey. We herein describe their isolation and subsequent resolution using chiral chromatography. The absolute configuration of each enantiomer was determined by a combination of Mosher ester analysis and comparison with related natural and synthetic products. Electro-olfactogram (EOG) assays indicated that (+)-petromyroxol (1) possesses potent olfactory activity for sea lamprey.