Analytical results, including ash fusibility data, are presented by the Bureau of Mines for 10 major constituents in coal ash from 373 samples of commercial US coals. Determinations of SiO2, Al2O3, Fe2O3, and P2O3 were made by colorimetric methods, Na2O and K2O by flame photometry, TiO2, CaO, and MgO by a spectrochemical method, and SO3 by a gravimetric method. In bituminous coal ashes the silicon, aluminum, and iron calculated as oxides often make up about 90% of the ash.