Hydrodistillation of the dried leaves of eleven species of the genus Eucalyptus L'Hér., i.e., E. astringens Maiden, E. camaldulensis Dehnh., E. diversifolia Bonpl., E. falcata Turcz., E. ficifolia F. Muell., E. gomphocephala DC., E. lehmannii (Schauer) Benth., E. maculata Hook., E. platypus Hook., E. polyanthemos Schauer, and E. rudis Endl., harvested from Korbous arboreta (region of Nabeul, northeast of Tunisia) in April 2006, afforded essential oils in yields varying from 0.1+/-0.1 to 3.8+/-0.1%, dependent on the species. E. astringens and E. ficifolia showed the highest and the lowest mean percentage of essential oil amongst all the species examined, respectively. Analysis by GC (RI) and GC/MS allowed the identification of 138 components, representing 74.0 to 99.1% of the total oil. The contents of the different samples varied according to the species. The main components were 1,8-cineole, followed by trans-pinocarveol (1), spathulenol (2), alpha-pinene, p-cymene, (E,E)-farnesol, cryptone, globulol (3), beta-phellandrene, alpha-terpineol, viridiflorol, and alpha-eudesmol. The principal-component and the hierarchical-cluster analyses separated the eleven Eucalyptus leaf essential oils into seven groups, each constituting a chemotype.