The decline in fertility in societies that experience demographic transition process, causes a proportional decrease in children in the total population. On the other side, since the transition process has not yet been completed, there is no significant increase in the share of the elderly population in the total. The working age population is increasing with the proportional decrease of the child and elderly population. This situation provides an opportunity for economic development and this special period is called "demographic window of opportunity" in the literature. This period can also be characterized as a “demographic gift” or “demographic bonus” in some studies. In today's conditions it is stated that the "demographic window of opportunity" period ends with population aging. As a matter of fact, if 15% of the population is 65 and over, the society is considered to have aged. The window of opportunity period is temporary. Therefore, it is important to create more employment and use resources more rationally during this period. As a matter of fact, the economic growth experienced by Japan after the 1960s and other East Asian countries after the 1970s is associated with the demographic window of opportunity. If this opportunity cannot be evaluated, the process can turn into a 'demographic window of crisis'. The demographic window of crisis is a process of national impoverishment, social turmoil and conflict caused by the inability of this group to be used efficiently in the Special Period that occurs when the 15-64 age group covering the working age reaches the highest rate. The main reason for this is that despite the high increase in the supply of labor, the demand for labor remains insufficient. Because it is thought that low employment and its negative effects will manifest themselves in both economic and social areas. This concept is the opposite of the demographic window of opportunity. A window that opens in countries such as Brazil, Venezuela, Tunisia is a demographic window of crisis, not a demographic window of opportunity. Because in some of these countries, there have been serious turmoil and conflicts; in other some, political powers have been overthrown. Finally, it is possible to say that the aim of the study is to show the formation processes of the demographic crisis window with historical and comparative examples and to introduce this concept into the literature. In this study, quantitative data compiled from national and international institutions were analyzed and it was determined that the process was experienced as a demographic window of crisis in countries such as Tunisia and Brazil. Moreover, it has been shown with a some tables and graphs that the same process is rapidly evolving into a demographic window of crisis for Turkey too.