The actual number and condition of Japanese patients in persistent vegetative states have not yet been fully understood. The aim of this study is to investigate the epidemiology of patients in persistent vegetative states in the Aomori prefecture. We sent questionnaires regarding gender, age, cause of persistent vegetative state, and residence of patient to all medical institutions in the Aomori prefecture (n=682). Two hundreds and seventeen institutions (31.8%) replied to the questionnaire, and eleven hundred ninety-eight patients(Male/Female=381/817) were included. Patients over 80 years-old were the most common (63.4%), and cerebrovascular stroke was the major cause (64.4%) of persistent vegetative state. Nursing homes (48.1%) and hospitals (34.6%) were the main care institutions. Population based analysis revealed that 869 persistent vegetative state patients per million were cared for in the Aomori prefecture. This result was twice as many as was previously reported in Miyagi prefecture. The number of patients in persistent vegetative states will increase in the future, due to an increasing elderly population and a high incidence of stroke in this demographic. We therefore predict that increased medical and administrative support will be required in the future.