The chemical composition of the essential oils obtained from the leaves and stem-bark of Garcinia mangostana Linn. extracted by hydrodistillation were analyzed by GC and GC-MS. A total of 64 and 101 constituents, representing 96.1 % and 97.5 % of the total oil were identified in the leaves and stem-bark essential oils, respectively. β-caryophyllene (17.3 % - 21.1 %) was the most abundant constituent common in both oils. The essential oils were toxic to Artemia salina with LC50 value of 1.70 μg/ml and 5.15 μg/ml for leaves and stem bark oils, respectively. The antibacterial activities of the essential oils were carried out using agar well diffusion method. Garcinia mangostana stem-bark essential oil was more active against the tested bacteria