Since the beginning of the 90’s inequality, once again, become one of the central issues of the economic debate from different perspectives: theoretical, applied and of policy. Not only increased the attention toward the inequality within countries, but also toward the global one, that is the inequality between countries and between citizens of the world as they belong to a single community. The effects of globalization on inequality are still very controversial. According to some authors international integration has produced not only instability and recurring crises, but also a growing inequality within and between countries. For other authors, instead, inequality and poverty decreased with the globalization. This paper will analyze the issue of global inequality mainly from an empirical standpoint. First of all, however, it will be discussed some issues related to the definition of the phenomenon with reference to the theoretical as well to the normative aspects. The empirical analysis will be undertaken by distinguishing the weight of the inequality between countries from that within countries on global inequality. Changes of synthetic indexes will be calculated, but also the differences in income’s distribution in each country will be analyzed. This kind of analysis, innovative with respect to the traditional ones, will allow to observe how the differences in the income’s distribution of industrialized and of developing countries can justify phenomena of the global economy such as, for example, migratory flows.