Neuroeconomics is a recent, fast developing area of cognitive neuroscience, investigating the brain mechanisms involved in economic decision-making. It is an intrinsically interdisciplinary field, taking advantage of several mature areas of research including behavioral economics, neuroscience of reward, and reinforcement learning theories. This is a selective review of experimental evidence related to some key concepts of this vast domain, starting from early neuropsychological evidence of the role of the prefrontal cortex in decision-making and adaptive learning from experience. The role of the reward system, delineated by animal studies and explored in humans by means of functional neuroimaging methods as a key mechanism responsible for behavioral learning, has been extensively investigated in decision-making situations involving uncertainty, temporal delay, and the exploration of potential rewards. The theoretical framework of prospect theory has been used to investigate the neural mechanisms involved in anomalies of choice, in particular in loss aversion. Another important area of neuroeconomic research deals with the neural mechanisms involved in social contexts, i.e., those underpinning theory of mind and reciprocal trust. These multiple approaches are contributing to the rigorous study of individual differences in decision-making and of their neurobiological foundations.