The study shortly surveys the main characteristics of the income surveys carried out by the Hungarian CSO in the last half century, then examines how the incomes of the households and especially the income inequalities developed in this period. The changes in the income inequality are shown in several inequality measures in the study. The emphasis is on the Theil inequality measure, because it can be unequivocally additively decomposed into parts representing the differences in the mean income between the various social groups and their weights on the one hand and the average within group inequalities on the other. The decomposition enlightens how and to what extent the various personal, household and regional characteristics contribute to the income inequality within the population and how the extent of this contribution changes in time and because of what causes. Based on the data of the last two income surveys the study examines the contribution to the inequality not only on the basis of the per capita income, but also on that of the equivalent income. Finally, on the basis of the huge amount of empirical data the study makes a few summary statements.