The two proponents of ordoliberalism, W. Eucken and W. strongly Röpke, emphasised the weaknesses of J.M. Keynes' approach and the possible hazards of its practical application in economic policies. The purpose of this paper is to present the main objections that Eucken and Röpke raised to Keynesianism. Among them, the most prominent issue was inflation, which, according to both authors, is a side effect of Keynesian economics. Another criticism of Keynes was that he overlooked the importance of ethical principles, which could lead to adverse economic consequences and undermine the moral foundations of society. Eucken's and Röpke's observations are as valid today as they were in the authors' time, and can be a source of inspiration for economic theoreticians and practitioners who contribute to the process of establishing economic order.