Recent anatomoclinical and neuroimaging studies have suggested a possible relation between obsessional compulsive disorders (OCD) and some brain damage, such as frontolenticular lesions, basal ganglia cavitations and local glucose metabolism impairment. A poor frontocaudal regulation of the left hemisphere and an autonomic nervous system dysfunction in OCD patients have been supposed. To absess these morphofunctional abnormalities, an electrophysiological approach has been performed in 100 consecutive neurotic patients, screened with various neuropsychological tests and divided in two groups, 50 with OCD and 50 with anxious neurosis (ANX). Patients were submitted to EEG spectral analysis and BAEP studies and comparated with 25 age-matched normal controls. The mean alpha power in occipital regions was significantly higher in OCD patients and reduced in ANX patients. A significant reduction of the beta activity was recorded in frontal regions in both patient groups as compared to controls. A slight (p < 0.11) increase in I-V interpeak latency (IPL) vs. control group was observed in BAEP from left ear. A significant increase of the same IPL in OCD vs. controls (p < 0.025) was observed in BAEP from right ear. A slight n.s. reduction in III wave amplitude in OCD patients was observed in BAEP from left ear, whereas a highly significant reduction in the same wave amplitude from BAEP from right ear was observed in OCD patients. The above findings cold be account for both a frontotemporal and brainstem dysfunction with a probable involvement of serotoninergic central pathways, with a significant impairment of pontine segment in ANX patients and of mesencephalic region in OCD patients.