The chemical composition of the leaf oil of Manekia naranjoana (C. DC.) Callejas (Piperaceae) from Costa Rica was analyzed by capillary GC/FID and GC/MS. Fifty-five compounds were identified. Major compounds from the leaf oil were β-pinene (30.6%), α-pinene (18.8%), limonene (13.7%), and β-caryophyllene (6.1%). The oil presented very low toxicity to tumor and non-tumor cell lines, even though it contains components, such as α- and β-pinene, limonene and others, which have been shown to be cytotoxic. This is the first report of the chemical composition of the essential oil obtained from this species.