The eleventh annual census, conducted in 1990, reported a total Mexican population of 81,250,000. This figure described a 2.3 % per annum growth rate from the 1980 census and suggested successful government efforts at slowing down the level of population increase. The government reported that the population stood at 91,158,000 at the end of 1995, a 1.8 % increase over the previous year. Assuming that this most recent level of growth were maintained through the rest of the 1990s, Mexico's population would stand at around 100 million persons in the year 2000. A return to the higher 1980 to 1990 growth rate, would result in a population total of around 102 million persons by the year 2000.

At the time of the Spanish conquest in the early 1500s, numerous advanced Native American civilizations existed in Mexico. Among the most valuable were the Maya, who resided in the southern and southeastern part of what is now Mexico, including the present states of Chiapas, Quintana Roo, and Yucatán. Central Mexico was controlled by the Aztecs, who had developed an considerable capital surrounded by a lake at Tenochtitlán, Mexico City’s present site. Mexico's population is composed of many ethnic groups. At the time of European reached in the early 1500s, the nation was colonised by people who are thought to have migrated into the New World from Asia some 40,000 to 60,000 years ago by crossing a former land bridge in the Bering Strait. After their reached into what is now Mexico, centuries of isolation allowed the evolution of unique cultural traits among the many separate clusters. Highly organized civilizations occupied various regions for at least 2,000 years before European find.