Gnetum species have been traditionally consumed as food and used as folk medicine to treat various pathological conditions. Ten compounds including three simple phenolic compounds (1-3), five stilbenoids (4, 5, 8-10), and two C-glycosyl flavanones (6 and 7), were isolated from the stems of Gnetum macrostachyum Hook. f. The structures of these compounds were elucidated by the analysis of spectroscopy data and their comparison with the reported values. This is the first report of the isolation of compounds 1-4 and 6-9 from G. macrostachyum. Compounds 1-3, 6, and 7 have not been previously reported from the genus Gnetum. The C-glycosyl flavanones in G. macrostachyum can be used as chemotaxonomic markers.