Eight polycyclic quinines and hydroquinones were isolated from marine sponge Xestospongia spp. They are halenaquinone (1), halenaquinol (2), 14-methoxyxestoquinone (3), 15-methoxyxes-toquinone(4), xestoquinone (5), 15-chloro-14-hydroxyxestoquinone (6), adociaquinone A (7) and adociaquinone B (8). Biological screening revealed that compounds 7 and 8 possessed in vitro cytotoxicity against KB 16 and HEP-3B tumor cell lines.