This article compares cabinet institutions for coordinating the transposition of EU legislation in Hungary, Poland and the Czech Republic. It examines how national executives have adapted to European integration and what factors have shaped institutional variation across countries and over time. During pre-accession, the Hungarian, Polish and (to a lesser extent) Czech cabinets established strong core executives for tracking EU-related legislative commitments, monitoring progress and reviewing the quality of transposition. After accession, the cores in all three cabinets loosened the grip on transposition, although to different degrees. The analysis shows that, if sectoral factors are kept constant, variation in the patterns of national adaptation can be explained with reference to external incentives and constitutional rules. High benefits of transposition before accession encouraged centralization, particularly in prime-ministerial cabinets. Fewer incentives under full membership contributed to a halt or reversal in core executive ascendancy, especially in ministerial-type cabinets.