The ability to monitor performance and behavior is crucial for goal-directed, adaptive behavior in a changing environment. Performance monitoring has been extensively investigated using behavioral, electrophysiological and hemodynamic measures, and is still in the focus of many research projects. This paper gives an overview on neuroimaging of performance monitoring and the models which arose from several research approaches, taking into account the knowledge stemming from electrophysiological and lesion studies. Particular emphasis is put on error detection and response conflict monitoring, but also at motivational factors. Furthermore, the paper presents and discusses data from an fMRI study investigating the influence of error relevance on the hemodynamic correlates of error processing. By instruction and financial reward manipulation, the relevance of errors were block-wise modulated in a flanker paradigm. The results suggest that the engagement of the posterior frontomedian wall (pFMC) previously shown to be involved in performance monitoring is dependent on error relevance.