The essential oil of leaves, stem bark and wood of Araucaria excelsa were prepared by hydrodistillation. Analysis of the oils by GC and GC-MS resulted in the identification of 78 compounds. The diterpene; phyllocladene (37.86%) is the major compound of leaves oil, while α-pinene (16.46%) and caryophyllene oxide (15.71%) are the major components of bark oil. The diterpenoids; kaurene, isopimarol and phyllocladanol are the major constituents of wood oil in relative percentage of 18.59%,12.09% and 10.73%, respectively. The major component of the leaves oil; phyllocladene was isolated and its structure was established by spectral data (UV, IR, MS, ¹H- and ¹³C-NMR). All the prepared oils and phyllocladene exhibited marked antimicrobial and antifungal activities.