Abstract Firesh leaves of Alpinia zerumbet and A. purpurata (Zingiberaceae) were collected in Rio de Janeiro city and subjected to hydrodistillation; their chemical composition was analyzed by GC/MS. These species are used as ornamental plants and in folk medicine. Variations in the leaf oils content and composition of A. zerumbet were found between April and August 2005. In April, the main constituents identiified in leaf oil of A. zerumbet were terpinen-7-al (40.5%) and sabinene hydrate (15.4%); in August, the major components identiified were terpinen-4-ol (29.4%) and 1,8-cineole (23.1%). Leaf oil of A. purpurata was rich in P-pinene (34.7%) and Î±-pinene (11.8%).