Background: Razi Psychiatric Hospital is one of the most important mental hospitals in Iran. The majority of the patients who have committed crime are treated in this hospital. This study surveys the process of diagnostic assessment, care and rehabilitation of criminal inpatients of Razi hospital. 
Materials and Methods: This is a descriptive-analytic study. The statistical population of this research incudes all of the patients of the hospital during winter 2015. The population was chosen using a non-random sampling method. The data was collected using a researcher-made form that included characteristics such as demographic, social-economic situation, diagnosis, the treatment they get and the type of the crime they had committed. In addition, the diagnosis and treatment information that was collected in patients’ cases using DSM-IV-TR, was also used. The HCR-20 checklist was piloted to assess the risk level. The collected data was checked using SPSS. 
Findings: During three months of winter in 2015, the number of criminal inpatients in Razi Hospital was 153 (17 females and 136 males). The findings showed that the treatment that was served for them wasn’t different from the non-criminal patients’ treatment. The only treatment they received was regular doctor visits and drugs. No organized psychiatric, rehabilitation and educational service was provided. Also there is no follow-up program defined for these patients. Although the 
forensic medicine doesn’t send these patients to this center to only treat them but to assess their risk level, for which there is no organized program.
Conclusion: Criminal patients need practices more functional than what is currently being provided. This study shows that the level of the Razi Hospital’s service needs improvement and needs its special high secured section to assess and treat the criminal psychiatric patients.