Abstract The composition of the essential oil from yacón tubers (Polymnia sonchifolia) was analyzed by capillary GC and GC/MS. Sixty-one components, representing 97.7% of the total oil were identified. The main constituents of the oil were α-pinene (33.5%), neo-abienol (15.7%), cis-abienol (15.4%), trans-abienol (7.0%) and 8,12-epoxy-14-labden-13-ol (2.8%). The oil from yacón tubers was also subjected to out odor evaluation by GC-MS-O and AEDA. Nine aroma-active compounds were detected and 2-acetyl-1,4,5,6-tetrahydropyridine was the odor characteristic compound, creating the yacón odor.