This paper presents an initial approach to the study of a little-known population: that of persons aged 100 years and over. As a result of declining birth and death rates, the country's age pyramid is undergoing a transformation process. Mexico's age structure profile is shifting from a young population towards an older one. In the next few years we will witness a rapid increase in the elderly population. People over 65 will become the age group with the highest growth rate and in a few decades that age group will have more population than that of persons under the age of 15. The issue of pensions and retirement will become the center of the country's financial planning efforts. We will need new social security schemes to adapt to an older country. This demographic shift towards aging will be one of our main concerns in the remainder of the twenty-first century.