This paper presents a historical analysis of the restoration of the stuccowork and mural paintings at the Teotihuacan site (see also the paper by Rubén Cabrera Castro, abstracted in this issue for the history of restoration of architectural elements at the same site). The periods of excavation beginning in 1905 are grouped in four stages, and the work accomplished on wall and floor coverings as well as on the sculptural elements of the stuccoed stone is described at each stage. The present needs of treatment and protection are still critical.