Most previous studies of mortality among mental patients dealt only with an in-patient population or with in-patient and out-patient populations of a mental hospital. A communitybased study was performed to analyze the mortality among mental patients in Kochi Prefecture. Schizophrenics and alcoholics were selected out of all mental patients for analysis. The relative risk of death among male and female schizophrenics and male alcoholics were two or three times higher than that among the general population. Especially, a younger group (30-49 years old) had higher relative risk than an older group (50-79 years old) among both patients. Therefore, to decrease the mortality among the mental patients, it is important to provide adequate health and medical care to younger patients. Among male and female schizophrenics, high relative risks were found for suicide, heart disease and accidents. The relative risk of death among the female patients was higher than that among the male patients. Among male alcoholics, high relative risks of death were observed for liver cirrhosis, suicide, heart disease, accidents, pneumonia and cerebral vascular diseases. In conclusion, the development of a community mental health care system, as well as rapid progress in psychiatric pharmaco-therapy, is necessary to decrease the mortality among mental patients.