The aim of the paper was to compare income inequality and poverty for different types of Polish households distinguished by the number of children. Special attention was paid to changes in income distribution observed in the period 2014 - 2016, when the child benefit programme called Family 500+, aimed at supporting Polish families with children, was launched. Under the programme, parents can receive a tax-free benefit of PLN 500 (about EUR 120) per month for the second and any consecutive children until they reach the age of 18. The basis for the calculations was microdata coming from the Household Budget Survey conducted by Statistics Poland. It is the basic source of information on the revenues, outgoings, quantitative food consumption and other aspects of the living conditions of particular groups of the population. The data obtained from this survey allow for the analysis of different factors influencing income distribution and its inequality. The following statistical methods were used to analyse the data: estimation of Dagum distribution parameters using maximum likelihood method, estimation of inequality and poverty indexes, estimation of concentration curves, parametric hypothesis testing for differences between income characteristics. For inequality analysis, besides the popular Gini index, which is known to be proportionally oversensitive to changes in the middle-income distribution, we used the Zenga index and the Zenga “point” inequality measures dedicated to detecting changes in each income quantile. To conduct poverty analysis we estimated at-risk-of-poverty rates, as well as the poverty gap and poverty severity indices, allowed us to measure the intensity, depth, and severity of poverty for groups of households. The analysis revealed substantial discrepancies between groups of households differing in the number of children. These discrepancies were observed not only between the groups but also within them. It is worth noting that the changes of income inequality and poverty observed for families with higher number of children turned out to be statistically significant in the period under consideration.