Following our phytochemical studies of Costa Rican plants, in this work we report the isolation and identification of eight compounds from aerial parts of Zanthoxylum setulosum (Rutaceae). They were identified as the alkaloid skimmianine, the lignans savinin, kusunokinin, sesamin, syringaresinol and the isopentenyl ether of pluviatol, the amide aurantiamide acetate, and the triterpen lupeol. This is the first report of isolation of skimmianine from the leaves of Z. setulosum and its presence confirm that quinoline and benzophenanthridine alkaloids, can be considered as chemotaxonomic markers of this genus. All the isolated compounds were characterized by spectroscopic methods (including 1H-NMR, 13C-NMR, HMQC, HMBC and NOESY) and comparison with the literature data.