Among the products generated in the processing of iron ore, the mud washing, in most cases, is stored in tailing dams without a commercial use. This study aimed to evaluate, at the technical point of view, the application of mud washing iron ore in Portland cement mortar. Specimens were molded with varied proportions of cement, sand and mud washing in powder and then submitted to physical and mechanic tests. The results showed that the replacement of sand by the mud washing (emphasis to 20% substitution) improved the mechanical performance of mortars, besides providing a reddish pigmentation. It evidences the technical feasibility of the material under study.