Event-related potentials (ERPs) can serve as markers for cognitive processing stages. Identification of those ERPs altered in schizophrenia offer information about cognitive dysfunction. Auditory evoked potentials (AEPs) were elicited within an oddball paradigm in 35 schizophrenic patients and compared with 35 healthy controls. N100 and P200, as well as N200, frontal P300 and parietal P300 subcomponents, were separated using dipole source analysis. The amplitudes of the N100 and the parietal P300 measured in schizophrenics were diminished. The input-related processing stages (N100 and P200) were not altered, whereas later, the deviant and task-related processes (N200, frontal P300, parietal P300 and reaction time) were significantly prolonged in schizophrenia.