In this paper the author considers recent extensions of the concept of economic rationality and of the model of economic agent. These extensions are primarily due to contemporary achievement of economics and related disciplines, notably congitive psychology and neuroscience. These results allow economists to bypass the limits of the standard model of homo oeconomicus, which has been subject to critiques of many social scientists (including economists), who rightly argued that its view of human cognition and decision capabilities has been exceedingly restricted and narrow. The author surveys and describes key ingredients of a newly emerging model of economic agent - homo postoeconomicus, who extends the neoclassical model of rational action to account for prosocial preferences, cognitive constraints, as well as neurobiological mechanisms of decision-making. In sum, this new model has its advantages over the conventional homo oeconomicus, but also is not free of substantive drawbacks, which so far has failed to contribute to genuine advancement of our knowledge about the nature and causes of human action.