Abstract The essential oils of seven samples of Ocimum campechianum and five samples of O. gratissimum cultivated in the state of Pará were obtained by hydrodistillation and analyzed by GC and GC-MS. The most abundant components identified in the leaf oils from O. campechianum were: eugenol (32.2% - 60.6%), methyleugenol (60.6% - 69.5%), 1,8-cineole (0.9% - 19.7%), and elemicin (0.2% - 65.9%). The most abundant components identified in the oils from O. gratissimum were: Thymol (13.1% - 36.2%), γ-terpinene (0.2% - 28.1%), 1,8-cineole (0.0 â 25.2%), and p-cymene (4.4% -19.9%). The results reveals the occurrence al least four types of O. campechianum in the State of Pará, and at least two types of O. gratissimum. The O. gratissimum studied here belongs to variety macrophyllum.