The frequency pattern through time for periostitis in the long bones of three ancient Mexican populations was carried out to understand the distinct treponematosis and the particular signature each leaves on the bone (Bejel, Yaws and Syphilis). From the results gained from the patterns from each population three sequencial phenomenon were established, each different from the previous and different from each other. The initial sickness has all the characteristics of Bejel and is present since 3100 b.C. in Tlatilco. This same pattern we found in the population of Marismas Nacionales in Nayarit (Pacific Coast) with dates after A.D. 1150-1300. It is after the last cultural period (Post Classic, 1300-1521) that we find a change, the population of the metro line excavations has two manifestations, on one side the skeletons of route II show a pattern that corresponds to a new sickness, Yaws. And the samples obtained from routes I and III reflect a pattern of syphilis. The change between the treponematosis in ancient Mexico is found in the epoch above the Mexicas of the Central Highlands of Mexico. The Mexicas came from northern Mexico, an area where it has been reported that Yaws was endemic. Therefore the possibility exists that the Mexicas shared this sickness before their migration and in this way arrived in Central Mexico. Another possibility is that during the period between 3100 b.C. to A.D. 1300 the drastic bicultural event caused large transformations and did not permit the continuation of the transmission of Bejel. The simultaneous presence of Yaws and Syphilis found in the skeletal samples from the Metro lines from Mexico City may be caused by the lack of precision in the chronology of the finds and for this reason we may have skeletons of individuals from Lines I and III that had contact with European populations and the new sickness, Syphilis. Therefore we have the presence of two dramatic changes in these populations, involving two invasions, the Mexica and the Spanish, each could be the decisive factors in the yield and or transformation of treponematosis in ancient Mexico