The essential oils from the aerial parts of Satureja boliviana Briq. and S. brevicalix Epl. (Lamiaceae) from Cusco Department, Peru, were obtained by hydrodistillation in 1.03% (v/w) and 0.96% (v/w) yields related to dry weight. By GC–MS analyses, 65 compounds were identified in both oils. Oxygenated monoterpenes constituted 81.5% and 87.0% of the oils of S. boliviana and S. brevicalix, respectively. In both oils, menthone (24.2% and 35.7%) and isomenthone (29.7% and 25.1%) were the main components. For S. boliviana, some differences were found compared with oil analysed in earlier studies, which could suggest the possible occurrence of chemical types. © 1998 John Wiley & Sons, Ltd.