The economic reconstruction of Belgium after the Second World War took place under conditions largely different from those in neighboring countries. A particular configuration of favorable circumstances permitted a very rapid economic recovery, subsequently known as the “Belgian Miracle.” But this miracle was shortlived. From the mid 1950s the Belgian economy was already showing signs of weakness that put it at a disadvantage relative to its competitors: relatively slow growth, insufficient investment, little advance in productivity. The legacy of this period may still be a burden forty years later. This chapter reviews the characteristic features of Belgian growth after the war and examines the way in which they were influenced by the Marshall Plan and the European Payments Union. The relative prosperity of the Belgian economy in 1948 is first considered. Then the structural weaknesses which had appeared by the late 1950s and their principal causes are discussed. Finally, some hypotheses about the role of the Marshall Plan and the European Payments Union in the relative weakness of the Belgian economy are proposed.