Introducing the discussions and practices of Polish etatism in 1930's, this article presents the historical process that the state control was strengthened and etatism became a main development strategy of the Polish government. One of the main problems of the economic policy of interwar Poland was economic backwardness and stagnation. The economic liberalism was a main current of economic ideology in the government (as an at least official standpoint), as well as the industrial world and academic circles. However, the economic liberalism and the political democratization couldn't solve these economic problems. The political situation was stabilized by Pilsudski's Coup D'etat, but the economic structural problem was still left (Chapter 1). Chapter 2 introduces arguments about interventionism and the controversy over an economic planning. The thoughts of an economic planning of the Polish Communist Party of Poland (KPP), the Polish cooperatism, the economic calculation debate, and the development policy of technocrats, would be worth paying attention. The so called "April Constitution" (1935) and the Great Depression (1929−1935) are analyzed in Chapters 3 and Chapter 4. The Great Depression shook the trust in market and the fundamental idea of economic liberalism. In 1935, new constitution was promulgated, and the president got a strong authority. Such a situation strengthened the tendency to etatism. In Chapter 5, the Central Industrial Region (COP) constructed on the base of etatistic ideology is empirically analyzed. It seemed effective not only in temporary economic stabilization, but in structural change of Polish economy that stands in long−term perspective. However, the construction of the Central Industrial Region was interrupted by World War II.