The US demographic overview for the last 100 years demonstrated the fact that the percentage of elderly people has considerably increased for a number of reasons to be analyzed. It is necessary to underline the fact that the significant factor in the population growth is related to large retirement settlements and increased recreational opportunities. Besides, the research demographic center, having developed a report of elderly population growth, explained this phenomenon with sunny and warm climate; it is necessary to stress that improved conditions for retired people impacted death rate reduction. Rapid increase of elderly people can be observed in Southwest of the USA; it is connected with high immigration level, as it was informed by Immigration Subcommittee of the USA. The entrance of more than 1 million illegal and legal immigrants influenced the increase of general population rate in the country, providing impact on the number of elderly people living in the USA. (US Population Growth, 2009) The analysis of US trends influencing the growth of the population is to be performed through national, economical and regional trends development. It should be stressed that the expansion of business sphere, economic opportunities and creation of larger number of working places impacted the population rate over the last century. The United States is considered to be the richest nation; its economy is evaluated in $13 trillion allowing the population enjoying constant raise of living standards. Comparing the country to other nationalities’ trends, it is necessary to underline the fact that China stands near American population structure on the basis of economic growth analysis. Taking into account gradual modernization of Chinese republic, one should stress that the population is on the way to progressive urbanization through industrialization of agrarian economy and modernization of coastal cities. The transformation of military structures and country’s position strengthening on the international level impacted population restructuring and national power. Nevertheless, the contrast population trends to the USA can be presented on the basis of Iranian domestic trends analysis. the country faces deep structural weaknesses in economic development, demographic pressures and political uncertainty. High unemployment level is one of the central problems affecting population internal structuring; it is necessary to stress that the nation suffers pronatalist policies reducing the population growth and leading to considerable demographic pressure. (Gordon, and Button, 2008) Dependency ration is considered to be age-population ratio covering the dependent and productive part including people presenting labor force, and those who do not. The 20th century showed a steady rise of age dependency ratio; in accordance with scientific analysis, there is a sharp necessity in changing the conventional thinking ways about dependency ratios providing impact on US elderly population. The demographic aging problems are related to economic dependency. It is necessary to stress that the changes in labor force participation covered by age-sex structure will lead to the balance shift of non-working older people to working ones. As a