A neuropsychological etiology has been suggested for lack of insight in schizophrenia patients, mainly based on frontal, right parietal, right hemisphere, or diffuse cerebral dysfunctions. The aim of this study was to investigate the neuropsychological pathogeny of lack of insight in schizophrenia patients. We examined a sample of 40 DSM-III-R schizophrenia inpatients admitted because of a recrudescence of symptoms. Schizophrenic symptoms were evaluated through the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms. Neurologic explorations included an assessment of frontal neurologic signs, abnormal involuntary movements, and soft neurologic signs. Lack of insight was assessed through three items from the Manual for the Assessment and Documentation of Psychopathology (AMDP). A global index from these three items (lack of feeling ill, lack of insight, and uncooperativeness) was obtained. A neuropsychological battery composed of tests involving many functional areas of the brain was used. No correlation between bad performance and lack of insight was found on any test. On the contrary, lack of insight was associated with better performance on immediate verbal, immediate visual, and delayed visual memory tasks. Moreover, the three components of lack of insight were extracted as an independent factor when they were included together with the positive and negative symptoms, neurologic abnormalities (frontal and soft neurologic signs, and abnormal movements), and a global measure of cognitive performance. The results of the study do not support the neuropsychological hypothesis of lack of insight. However, these results are inconclusive because of inadequate statistical power. Nonetheless, the absence of correlation between lack of insight and cognitive disturbances and independence of lack of insight from the clinical symptoms, neurologic signs, and cognitive disturbances suggest that lack of insight could be a primary symptom resulting directly from the schizophrenic process.