Decreased quality of life is often an important cause or consequence of psychiatric illness, and needs to be included in a comprehensive treatment plan. The authors aimed to identify how psychiatric patients characterize the quality of their lives compared to others who are suffering from a chronic physical illness (diabetes) and healthy individuals. A total of 100 psychiatric patients were recruited from Dokuz Eylul University Psychiatry Department outpatient clinic. Of these, 34 had 4th edition Diagnostic and Statistical Manual diagnosis of alcohol dependence, 38 had schizophrenia, and 28 had bipolar disorder. A total of 35 patients with diabetes and 49 healthy individuals were also included in the study. The World Health Organization's Quality of Life Questionnaire was used to measure the quality of life. Patients with alcohol dependence, bipolar disorder, and schizophrenia scored lower than healthy subjects on the physical aspects of quality of life. Patients with schizophrenia had lower scores in the psychological domain compared to patients with bipolar disorder, patients with diabetes, and healthy subjects. In the social relationship domain, patients with schizophrenia and alcohol dependence scored lower compared to healthy subjects. Patients with schizophrenia were worse with respect to social relationships than bipolar patients and diabetics. World Health Organization's Quality of Life Questionnaire is useful for evaluating the needs and targets for interventions in psychiatric patients.