Objective: In this study, it was aimed to define the clinical characteristics, causes of death, disease and treatment of patients who died while being followed for severe mental illness. Method: The study was carried out in ten community mental health centers from six provinces. The clinical characteristics, causes of death, course of the illness and treatment characteristics of the patients who had a death report from the date the community mental health centers were opened until the start date of the study were analyzed by retrospective file scanning method. Results: In an average of 52 months, files of 3715 patients were examined. There were death declarations for 106 patients. The diagnosis of most patients with death declarations was schizophrenia (78%), most of them were male (66%), mean age was 57, mean disease duration was 24 years. The rate of multiple antipsychotic medication use was 61%. The most common comorbidities were metabolic syndrome (36%), hypertension (22%), diabetes (18%) and chronic obstructive pulmonary disease (15%). The most frequently reported causes of death were cardiovascular diseases (39%), infectious diseases (14%) and cancer (11%). Conclusion: Individuals with severe mental illness followed up in community mental health centers are mostly die due to preventable natural causes of death. Therefore, a sensitive approach should be taken to evaluate psychiatric and other medical conditions together. In our country, there is a need for natural follow-up studies investigating the average age of death and causes of death of individuals with severe mental illness.