Analysis of the leaf essential oils of Eucalyptus robusta, E. resinifera and E. gomphocephala by GC and GC-MS resulted in the identification of 20, 14 and 22 components, comprising 88.4 , 89.5 and 89.5 % of the oils, respectively. The composition of the three oils varies both qualitatively and quantitatively. The oils are characterized by high concentration of sesquiterpene alcohols (α-, β-and ɣ-eudesmol and viridiflorol), oxygenated monoterpenes and phenolic ethers. Cineole ranges from 4.6 to 16.8%. trans- and cisMethylisoeugenol were found only in the oil of E. gomphocephala , these compounds have not been reported in Eucalyptus before. The oil of E. resinifera exhibited a significant antibacterial and antifungal effects, while that of E. gomphocephala showed a moderate antibacterial and strong antifungal activities. The oil of E. robusta showed a weak antibacterial effects and no antifungal activity against the tested microorganisms.