The present thesis taps into the field of neuropsychological decision-making research. In this field it is common to distinguish between decisions under ambiguity and decisions under risk. In situations under ambiguity the decision maker has no information about the consequences and their probabilities of occurrence, which is why she/he has to rely on her/his intuitions and experiences with the situation (e.g., Bechara, Damasio, Damasio, & Anderson, 1994). In contrast, in situations under risk information about consequences and probabilities is given and the decider can process them to make a decision (e.g., Brand, Labudda, & Markowitsch, 2006). In their model of decision making under risk, Brand and colleagues (2006) postulated the involvement of cognitive and affective processes. Over the years, several studies supported this assumption. However, little was known about the interaction between the underlying cognitive and affective processes and the associated neural correlates. The research for this thesis was conducted to fill this gap. The first study aimed to investigate the neural correlates of the interaction between decision making, additional cognitive demand, and stress. It was found that stress appears to trigger a shift from serial to parallel processing brain regions to prevent decision-making performance from decreasing, supporting the assumptions made in previous studies (Pabst, Schoofs, Pawlikowski, Brand, & Wolf, 2013; Plessow, Schade, Kirschbaum, & Fischer, 2012). The second study concentrated on the possibility that cognitive functions might have an important role in facilitating decision making in situations when both processing routes (affective and cognitive) are demanded at the same time. The results revealed that although affective stimuli (especially those of positive valence) interfere with the decision-making performance, participants with superior executive functioning seem to be unaffected and were still able to decide advantageously. In contrast, participants with inferior executive functions were affected and showed disadvantageous decision making. In the third study the focus of investigation was which subcomponents of executive functioning might be involved in decision-making situations with additional cognitive demand. The findings suggest the involvement of higher-level executive functions and lower-level executive functions in decision making when the cognitive route is additionally loaded by another cognitive demanding task simultaneously. In order to measure the additional cognitive load, a dual task consisting of a decision-making task and an additional cognitive task was used in each study. In conclusion, the findings suggest that in decision-making situations with additional cognitive and affective demand, underlying affective and cognitive processes interact in a way that they prevent a decrease of decision-making performance. The findings and the therefrom derived assumptions are discussed in detail and perspectives for future outcomes are given.