The essential oils of the aerial parts of three Baccharis species (B. articulata, B. myrtilloides, and B. rufescens) were examined by GC and GC/MS. The major constituents were for B. articulata: β-caryophyllene (16.8%), trans-nerolidol (15.6%); for B. myrtilloides: germacrene D (9.5%) and for B. rufescens: limonene (14.4%) and trans-nerolidol (14.5%).