This study investigated the codetypes of MCMI-II in a group of patients in psychiatric centers. 85 inpatient and outpatient subjects of Shahid Nawab Safavi and Shahid Esmaili Psychiatric Hospitals with the ultimate diagnosis of schizophrenia, mood disorders and substance related disorders were administered the MCMI-II Farsi version Questionnaire. The results suggested that for each of these disorders, a specific codetype can be identified. In other words, this questionnaire can be used as an assisting diagnostic instrument for axis I disorders in addition to personality disorders.