The aim of this study was to clarify the difference in the perception of family functioning measured on the Family Assessment Device (FAD) by Diagnostic and Statistical Manual-IV diagnoses (i.e. schizophrenia, major depressive disorder and bipolar disorder) and by raters (patients and family members). The subjects were 70 psychiatric outpatients paired with their family members (i.e. principal caretaker), divided into three groups based on the patient's diagnosis of schizophrenia (24 pairs), major depressive disorder (28 pairs) or bipolar disorder (18 pairs). They rated their perceived family functioning on the FAD. There was no significant difference in perceptions of family functioning between the three groups of family members, while there were differences between the patient groups in some FAD dimensions. Perceptions of family functioning were not significantly correlated between the schizophrenic patients and their family members. The perceptions of family functioning were correlated more strongly between patients and their family members in the bipolar group than between patients and family members in the other two diagnostic groups. As for the FAD Problem Solving dimension, the schizophrenia patients saw it more negatively than did their family members, whereas the depressive patients saw it more positively than did their family members. These results might reflect psychopathological characteristics of each disorder. When clinicians evaluate the family functioning of psychiatric patients, it is important to consider the diagnoses of patients as well as who assesses it.