Human error processing – a function that is essential for goal-directed behavior – has been proposed to be closely related to reward prediction. Both reward processing and performance monitoring are assumed to reciprocally interact with emotion and motivation. In the talk I will present data from ERP as well as fMRI studies investigating these relationships. In the first part, data from an fMRI study in which feedback informativity was varied during a task involving high response uncertainty will be presented. The results clearly demonstrate the role of the reward system in error processing. The rostral cingulate zone, the putative generator of the error-related negativity, is specifically activated by negative feedback, whereas the ventral striatum reacts to positive feedback. In the second part, ERP as well as fMRI results addressing the modulation of error processing by contextual variables, such as motivation, will be presented. The relevance of errors was modulated by differential instructions and financial incentives. The studies revealed larger ERN amplitudes and higher hemodynamic signal increases in the rostral cingulate zone, when errors were of high relevance to the individual. The data will be discussed with respect to the reward-based reinforcement learning theory of the ERN proposed by Holroyd and Coles (2002). Furthermore, similarities of the networks involved in the detection of different error types will be discussed.