<jats:title>Abstract</jats:title><jats:p>Hydrodistillation of the dried leaves of 13 species of the genus <jats:italic>Eucalyptus</jats:italic> L' <jats:sc>Hér</jats:sc>., <jats:italic>viz., E. bicostata</jats:italic> <jats:sc>Maiden, Blakely</jats:sc> & <jats:sc>Simmonds</jats:sc>, <jats:italic>E. cinerea</jats:italic> F. <jats:sc>Muell</jats:sc>. ex <jats:sc>Benth</jats:sc>., <jats:italic>E. exerta</jats:italic> F. <jats:sc>Muell</jats:sc>., <jats:italic>E. gigantea</jats:italic> <jats:sc>Hook</jats:sc>. <jats:sc>f</jats:sc>., <jats:italic>E. gunnii</jats:italic> <jats:sc>Hook</jats:sc>. <jats:sc>f</jats:sc>., <jats:italic>E. macarthurii</jats:italic> <jats:sc>Deane</jats:sc> & <jats:sc>Maiden</jats:sc>., <jats:italic>E. macrorrhyncha</jats:italic> F. <jats:sc>Muell</jats:sc>., <jats:italic>E. maidenii</jats:italic> F. <jats:sc>Muell</jats:sc>., <jats:italic>E. odorata</jats:italic> <jats:sc>Behr</jats:sc>., <jats:italic>E. pauciflora</jats:italic> <jats:sc>Sieber</jats:sc> ex <jats:sc>Sprengel</jats:sc>, <jats:italic>E. sideroxylon</jats:italic> A. <jats:sc>Cunn</jats:sc>. ex <jats:sc>Woolls</jats:sc>, <jats:italic>E. tereticornis</jats:italic> <jats:sc>Sm</jats:sc>., and <jats:italic>E. viminalis</jats:italic> <jats:sc>Labill</jats:sc>., harvested from Souinet arboreta (region of Ain Draaham, north of Tunisia) in June 2006, afforded essential oils in yields varying from 0.5±0.2 to 3.9±0.4%, dependent on the species. <jats:italic>E. cinerea</jats:italic> and <jats:italic>E. exerta</jats:italic> provided the highest and the lowest percentage of essential oil amongst all the species examined, respectively. Analysis by GC (<jats:italic>RI</jats:italic>) and GC/MS allowed the identification of 142 components, representing 81.5 to 98.9% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8‐cineole (<jats:bold>1</jats:bold>), followed by cryptone, spathulenol (<jats:bold>4</jats:bold>), <jats:italic>p</jats:italic>‐cymene (<jats:bold>2</jats:bold>), viridiflorol (<jats:bold>6</jats:bold>), globulol (<jats:bold>7</jats:bold>), <jats:italic>β</jats:italic>‐eudesmol, <jats:italic>α</jats:italic>‐terpineol (<jats:bold>5</jats:bold>), limonene (<jats:bold>8</jats:bold>), <jats:sc>D</jats:sc>‐piperitone, <jats:italic>α</jats:italic>‐pinene (<jats:bold>3</jats:bold>), cuminal, and <jats:italic>γ</jats:italic>‐eudesmol. The principal component and the hierarchical cluster analyses separated the 13 <jats:italic>Eucalyptus</jats:italic> leaf essential oils into three groups, each constituting a chemotype.