Objectives : The purpose of the study is to investigate the xerostomia in the chronic severe psychiatric patients in Korea because there were few reports on xerostomia in the psychiatric patients. Methods : The subjects were 61 psychiatric patients in the mental hospital by convenience cluster sampling. A self-reported symptom questionnaire was filled out by the three researchers on the basis of medical records by the informed consent. The stimulated salivary flow rate of the patients was measured by saliva sampling. Results : The subjects consisted of 45.9% of male and 54.1% of female. High school graduation accounted for 40.0% and 20.0% did not attend the school. The majority of the patients were medicaid recipients. Schizophrenia accounted for 86.9% and most patients were long term care recipients. A total of 68.9% of the patients suffered from salivary dysfunction. The medication in schizophrenia seemed to decrease the stimulated salivary flow rate and made the patients difficult in chewing and swallowing due to xerostomia and low saliva secretion(p<0.05). Conclusions : Medication in schizophrenic patients caused the salivary dysfunction. So the collaboration between the psychiatry doctors and dental hygienists is very important to improve the salivary secretion in the schizophrenic patients. The continuous and long term care of the xerostomia will help the patients maintain the good oral hygiene.