Abstract The essential oil from the leaves of Xylopia laevigata was obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry (GC/MS) and GC/flame ionization detector (GC/FID). Thirty-six compounds representing 97.48% of the crude essential oil were identified. The major compounds identified were -muurolene (17.99%), -cadinene (13.45%), germacrene D (9.09%), bicyclogermacrene (7.00%), -copaene (5.98%), and (E)-caryophyllene (5.43%). The biological activities of the essential oil against Trypanosoma cruzi epimastigote forms, yeast, bacteria, Aedes aegypti larvae, antioxidant properties and antiproliferative activity against tumor cell lines were investigated. The essential oil showed trypanocidal activity with IC50 value of 93.9±2.6 μg/mL. For antibacterial and antifungal activities, the best results were observed against Staphylococcus aureus (ATCC14458), Staphylococcus epidermidis (ATCC1228) and Candida tropicalis (ATCC 157), all with a minimal inhibitory concentration value of 100 μg/mL. The essential oil showed antioxidant capacity of 1468.96 μmol of TE/g in the oxygen radical absorbance capacity (ORACFL) assay. The oil showed moderate larvicidal activity with LC50 value of 632.36 μg/mL. The essential oil exhibited potent antiproliferative activity against all cell lines evaluated with total growth inhibition (TGI) value <40 μg/mL, exception for K562 cell line (TGI>250 μg/mL). The highest activity was observed against cell lines of UACC-62, NCI-ADR/RES and NCI-H460, with TGI values of 4.03, 4.26 and 8.37 μg/mL, respectively. For the VERO cell (non-cancer cell line), the TGI value was of 15.94 μg/mL. Keywords: Xylopia laevigata essential oil compositionantioxidantantibacterialantifungaltrypanocidallarvicidalantiproliferative activities Acknowledgements The authors are grateful to FAPITEC/SE (Editais 07/2009 and 10/2009), CNPq, CAPES and FAPESP for financial support, and Professor Dr Ana Paula do Nascimento Prata of the DBI/UFS for the botanical identification. This paper was presented by the author at the XX° Congress of Italo-Latin American Society of Ethnomedicine (SILAE), Fortaleza, Brazil, 19â22 September 2011.