Dense glass-ceramics for low firing temperature substrates were prepared by the addition of CeO2 flux to a glass of the MgO-Al2O3-SiO2 system. The glass powders were fabricated by melting at 1500-degrees-C and ball milling. Glass powder compacts prepared by dry pressing were heated at 800-1000-degrees-C for 0.5-4 h and sintered at 900-1000-degrees-C for 3 h. The crystallization behaviour and sinterability of the glass powder compacts were analysed by thermal and thermomechanical techniques, X-ray diffractometry and scanning electron microscopy. The addition of CeO2 prevents the formation of mu-cordierite phase in the glass-ceramics and improves the formation of alpha-cordierite phase. The activation energy of the glass containing CeO2 for crystallization was lower than that of the CeO2-free glass. Therefore, crystallization properties were enhanced. Because the crystallization onset temperature increased and the softening temperature decreased on the addition of CeO2, the sinterability increased and dense glass-ceramics were fabricated below 1000-degrees-C. The properties of the glass-ceramics containing CeO2 appeared to be correct for low firing temperature substrates.