Ample evidence from behavioral studies and structural/functional brain imaging suggests that cognitive control is fundamentally impaired in major depressive disorder (MDD), though the precise nature of this deficit is unclear. Although many studies indicate that brain areas involved in two critical stages of cognitive control, conflict monitoring and conflict regulation, exhibit attenuated activity when task performance is impaired, recent studies find that these brain areas are hyperactive when depressed participants perform comparably to controls (i.e. cognitive inefficiency). The purpose of the current set of studies was to clarify the nature of cognitive control in depression using event related brain potentials (ERPs) to investigate putative abnormalities in both conflict monitoring and regulation across three different domains (Botvinick, Braver, Barch, Carter, & Cohen, 2001). In the first two studies, it was found that depressed participants performed comparably to controls in tasks that tax interference control (Stroop) and behavioral inhibition (Stop-Signal). However, in the MDD group, ERPs indicated enhanced task-related effects at the conflict monitoring (N450) and conflict regulation (frontal P300) stages for the Stroop and attenuated effects in these stages (i.e., N2 and P300) for the stop-signal task. In the third study, it was found that depressed participants exhibited attenuated fronto-lateral positivity that was associated with conflict regulation during a task that taxed undetermined responding. This time, task performance was impaired in depressed participants. Collectively, these findings indicate that there is no 'universal' cognitive control deficit in depression. Rather, the nature of the deficit varies depending upon which domain of cognitive control is being challenged.