In this study the volatile constituents from leaves and fruits of Julocroton triqueter (Lam.) Didr. (Euphorbiaceae), a medicinal plant from northwest Brazil, were investigated by GC/MS. Twenty one compounds, which represent about 96% of the total constituents of the essential oil, were identified. Caryophyllene oxide, humulene epoxide II, trans-caryophyllene, occidentalol, á-humulene in the fruit and CM-carvyl acetate, spathulenol, CM-carveol, trans-caryophyllene, trans-carvyl acetate and á-humulene in the leaves were the principal components. From one fraction of the hexane extract of the fruits a mixture of fatty acids were identified as: dodecanoic, tetradecanoic, hexadecanoic, 9-octadecenoic, eicosanoic, trieicosanoic and tetracosanoic acids. The partial analysis of the non-volatile constituents (hexanic fraction) from fruit allowed the isolation and characterization of tetracosan-1-ol (identify by ¹H and 13C NMR, FTIR).