Informality is an alternative source of income to the lack of opportunities people have to get a job in the formal sector. This article presents the results of the review concerning informality and its determinants, noting that unemployment is the main cause, as well as demographic factors such as educational level and gender. On the one hand, the economic factors are associated with globalization, industrial development, economic cycles and real exchange rate, while the institutional aspects of labor market regulation are the determinants of informality and the corresponding implication.