Essential oils chemical constituents of leaves of O. gratissimum and O. campechianum of the Lamiaceae family, collected in Chocó of northwest Colombian, were obtained by microwave-assisted hydrodistillation and analyzed by gas chromatography coupled with mass spectrometry. A total of 33 and 37 compounds were identified in the essential oil of O. gratissimum and O. campechianum, respectively. O. gratissimum's main essential oils were eugenol (43.2%), 1,8-cineole (12.8%) and beta-selinene (9.0%); in the O. campechianum essential oil, the main components were methyl eugenol (12.0%), germacrene D (10.1%), and eugenol (9.0%). Main distribution of compounds in these essential oils are 25.0% monoterpenes hydrocarbons, 15.0% monoterpenes oxygenated, 35.0% sesquiterpenes hydrocarbons, 7.5% other oxygenated components for O. gratissimum, 33.9% sesquiterpenes hydrocarbons, and 10.7% their respective oxygenated derivates; for O. campechianum, the distribution was 10.7% monoterpenes hydrocarbons and 7.1% their respective oxygenated derivates and 3.6% phenylpropanes. According to the essential oils chemical composition of Ocimum gratissimum and O. campechianum, they are classified as eugenol and methyl eugenol chemotype, respectively.