The chemical compositions and antimicrobial activity of the fresh rhizome and flower oils of Hornstedtia havilandii were studied. The components present were analyzed using GC and GC-MS. A total of forty-eight constituents were successfully identified from the flower and rhizome oils, representing 93.4% and 89.6%, respectively. The most abundant components of the flower oil were β-pinene, (19.5%), β-elemene, (10.0%), β-cubebene, (6.2%), α-pinene, (5.6%), γcadinene, (4.3%) and germacrene D, (3.3%), while α-copaene, (10.2%), β-selinene, (8.4%), β-elemene, (7.0%), γ-cadinene, (6.9%), β-cubebene, (5.3%) and germacrene D, (5.3%) were found as the main components of the rhizome oil. The essential oils were tested for antimicrobial activity against Gram-positive bacteria, Gram-negative bacteria and yeasts. Both oils showed activity against the Gram-positive bacterium, Staphylococcus aureus, with moderate MIC values of 112.5 µg/mL, however, for Gram-negative bacteria, the flower oil showed weak antimicrobial activity with a MIC value of 225 µg/mL. Only very weak activity was shown against the yeasts Candida albicans and C. glabrata, with MIC values of 900-1800 µg/mL.