Loss on ignition, linear shrinkage, bulk density, apparent porosity, water absorption, water suction, compressive strength, microstructural properties and thermal conductivity values of the fired samples were investigated. The results obtained showed that the use of waste decreased bulk density and increased apparent porosity of sintered samples. Values on mechanical properties decreased, due to the increase in water absorption and water suction, but were higher than those required by the standards. Thermal conductivity of the mixture brick decreased by 20 % when spent earth from biodiesel filtration was incorporated, and up to a 40 % when glycerine was added. Therefore, biodiesel waste is suitable as secondary raw materials in ceramic brick production.