The UNAM Institute of Engineering participates on the project of rehabilitation of the Mexico City Metropolitan Cathedral. The bases of the project and the studies performed to support the decisions about the corrective measures, are described in the article, along with the results reached in the past 10 years of work. Even though some strengthening works are still in progress, the monument has already been bought to very acceptable safety conditions. In particular, the differential settlements that at the beginning of the project reached a maximum of 2.4m, have been reduced by about 1m.