Two new xanthone derivatives, named schomburgones A (1) and B (2), along with eight known compounds, including xanthones (3-8) and anthraquinones (9-10) were isolated from the bark of Garcinia schomburgkiana. Their structures were determined by spectroscopic analysis especially 1D and 2D NMR spectroscopies. All isolated compounds were evaluated for their cytotoxicity against five cancer cell lines (KB, HeLa S-3, HT-29, MCF-7 and HepG-2). Compounds 3-6 and 8 showed good cytotoxicity against all the five cancer cell lines with IC values in the range of 1.45-9.46 µM.