This work evaluates the use of the sludge resulting from the washing of iron ore produced by Mineração Urucum S/A, in Corumbá/MS, as an addition to clays used in the manufacture of ceramic products, mainly red ceramics. The ore processing process consists of crushing, washing and sieving. All the products generated, with the exception of the slurry, have commercial applications, and the slurry resulting from this process is deposited in settling basins, requiring more and more areas for the creation of new deposits. In order to answer the question of the validity of using mud as an addition to clays for the manufacture of ceramic products, test specimens were moulded with two types of clay, one from Corumbá/MS and the other from Campo Grande/MS, in mass proportions of 0%, 10% and 20%. The results indicate that although the sludge has a high iron content, it hardly alters the properties of the clays studied, improving some of their characteristics, such as water absorption, apparent porosity and shrinkage, opening up possibilities for utilising this waste.