Abstract The essential oil from fresh leaves of Piper cernum Veil. var. cernum Yuncker from Rio de Janeiro, Brazil was isolated by hydrodistillation and analyzed through a combination of GC and GC/MS. Compounds representing 92.9% of the oil volatiles were identified. Twenty six constituents were identified according to their retention indices and mass spectra. The major constituents of the oil were cis-dihydroagarofuran (32.3 %), Î±-pinene (10.2 %), Î²-pinene (7.4 %), 10-epi-Î³-eudesmol (7.1 %) and elemol (6.7 %).