Aims: A functional maturational delay in the central nervous system is dwelled upon in the pathogenesis of monosymptomatic nocturnal enuresis (NINE). In this study we studied whether according to controls N200 and P300, components of the event-related potential (ERP), which is related to aspects of cognitive processing, showed any difference in its topographic distribution in children within the age group 10-13 with monosymptomatic nocturnal enuresis and discussed its relation to the pathogenesis of MNE. Methods: We performed P300 in 18 patients with MNE and in 16 age-matched healthy subjects. P300 were evoked by an auditory oddball paradigm consisting of 150 tone bursts (80% 1 kHz; 20% 2 kHz). The latencies of the N200 and the P300 waves and the amplitude of the P300 wave were measured. Results: There was no statistical difference between the enuretic group and the controls in N200 and P300 latency and amplitude in the midline frontal (Fz), central (Cz), and parietal (Pz) recording site of the 10-20 International System. In the enuretic group while P300 amplitude in the Fz site was significantly less than the P300 amplitude in the Cz site, there was no statistical difference between the Fz and Pz P300 amplitude values. Conclusions: When different levels of maturational delay are considered in NINE, it may be claimed that maturational delay in children whose enuresis lasts until older ages will be different from those whose enuresis ends at an early age. The determination of P300 amplitude in parietal records being less in enuretics when compared to the controls may show that there are regional differences in stimuli processing rate/quality. (C) 2004 Wiley-Liss, Inc.