In this paper, we will provide some insights on solutions adopted for solving some major issues encountered in building the Italian Integrated System of Statistical Registers, namely: (i) the integration between surveys and registers, exemplified through the case of the relationships between the Continuous Population Census and the Population Register; (ii) the problem of stock-flows harmonization; (iii) the measure of accuracy of register aggregates; (iv) the data architecture design and implementation, including specific architectural solutions for privacy. We conclude by highlighting the major challenges that are still open.