Abstract: Disclosed is an unfired refractory composition comprising a refractory aggregate and a binder for the refractory aggregate, in which the binder comprises a water-soluble or water-dispersible siliceous binder in an amount of 1 to 20% by weight based on the refractory aggregate, a carbonizable organic binder in an amount of 2 to 15% by weight based on the refractory aggregate and a phosphate type hardening agent in an amount of 0.5 to 20% by weight based on the refractory aggregate.This refractory composition is moldable and hardenable at normal temperatures, and has an excellent mechanical strength not only at relatively low temperatures below about 500.degree. C. and high aggregate-firing temperatures but also intermediate temperatures between these low and high temperatures.