The results of some 50 chemical analyses of rocks collected from two ultramafic belts in the Central Cordillera of Guatemala are discussed. In these belts rodingites, pillow basalts and scarce metamorphic and acid igneous rocks are associated with the ultramafics in a "mélange". Partially serpentinized peridotites and serpentinites, as well as relict primary mineral phases, have compositions similar to those of alpinotype ultramafics. The association of rodingites and pillow basalts with these ultramafics agrees well with the ophiolitic character of the belts under discussion. It is noted that the submarine basalts have a more sodic character than recent oceanic tholeiites but this may be due to metasomatism during an episode of degradation. The present chemistry of the metamorphic and acid igneous rocks gives no obvious clue to their origin.