The chemical composition of the essential oil of the resin “Ladano,” from the plantCistus incanussubsp.creticus(L.) Heywood, was investigated by GC and GC/MS. Of the 55 compounds detected, 52 were identified, representing 97.42% of the oil. A drimane-type sesquiterpene hydrocarbon was identified as a new constituent of the oil. The manoyl oxide isomers were also isolated as a mixture, and one of them was characterized as ent-13-epi-manoyl oxide. Structural elucidations were performed by spectroscopic analysis, including1H-NMR,13C-NMR, DEPT, IR and MS techniques.