The essential oils of wild Clausena lansium collected in Hainan Island, China were extracted from leaves, flowers, sarcocarps and seeds, and then analyzed by using GC/MS. The main constituents of the essential oils were: beta-santalol (35.2%), bisabolol (13.7%), methyl santalol (6.9%), ledol (6.5%) and sinensal (5.6%) in the leaves; beta-santalol (50.6%), 9-octadecenamide (17.2%) and sinensal (4.1%) in the flowers; beta-santalol (52.0%), alpha-santalol (15.5%), farnesol (5.2%) and sinensal (4.0%) in the sarcocarps; and phellandrene (54.8%), limonene (23.6%), and p-menth-1-en-4-ol (7.5%) in the seeds.