Abstract: The invention provides a process for producing ceramic products using, as one of the materials, the sludge obtained by sewage treatment. The invention thus not only makes the sludge treatment unnecessary, but makes the sludge useful as a material for products. A plastic ceramic raw material and, if required, another raw material are added to either the sludge or the ashes obtained by burning the sludge, so as to prepare a body. The body thus obtained is molded into a desired shape, and fired to produce a ceramic product. The firing process prevents the product, containing the sludge, from emitting an offensive odor or being decomposed. The product may be used as a tile, brick block, or the like. Production conditions such as the proportion of each raw material used and the like may be suitably selected to obtain a ceramic product with a desired characteristic in respect of water permeability, from almost no permeability to a very high permeability.