EU-SILC will become one of the most important statistical data sources for the Federal Government's future Poverty and Wealth Reports, for comparing Germany's position with those of the other EU member states in the "open method of coordination", and for the international scientific community and international organisations. Hence this sample needs intensive quality control to ensure data quality. Ex ante quality control must take the form of selecting suitable survey methods, internal control of consistency of the data collected from each household, transparent data editing, reliable imputation methods and compensation for drop-outs by reweighting. Ex post consistency checks are needed in the form of comparison with other similar household samples, with administrative statistics and with macro-economic aggregates of the national accounts. In this paper the need for intensive ex post quality control is met with consistency checks in the form of a comparison between the results of EU-SILC and the microcensus and SOEP, which reveals significant deviations in the coverage of poorly integrated foreigners, small children and the level of education, as well as the ratio of house/apartment owners and the employment ratio. This causes serious distortions to the Laeken indicators calculated.