Essential oils extracted by hydrodistillation from leaves and roots of Ottoa oenanthoides Kunth (Apiaceae) were analyzed by GC/MS. The oils, obtained in yields of 0.10% and 0.66%, respectively, each contained four compounds, which were identified from their mass spectra and retention indices (RI). The major compound identified was 2-methoxy-8-methyl-1,4-naphthalindione (59.9% leaves, and 62.8%, roots), followed by 7-methoxy-1-naphthol (18.3% leaves and 17.3% roots), 2-naphthalenol (18.6% leaves and 15.0% roots), and 3-methoxy-2-naphthalenol (3.1% leaves and 2.1% roots). To the best of our knowledge, this is the first time that naphthalene derivatives have been reported for any species of the Apiaceae family.