Background: This study was conducted to validate the "staff attitude toward the use of coercion in the treatment of mentally ill patients" questionnaire and assessed their attitude in selected public psychiatric hospitals in Tehran city.
Materials and Methods: This is a descriptive and analytical study which was carried out on three hospitals of Tehran University of Medical Sciences, Iran University of Medical Sciences and social welfare and Rehabilitation University in 2015. The questionnaires were distributed to the participants and finally 273 questionnaires were used.  Data were analyzed using confirmatory factor analysis test. Moreover, ANOVA and independent t-test were applied to evaluate the participants' attitude on using coercion for treatment of mentally ill patients.
Results: Study findings revealed that 61% of participants were nurse and 11% were physicians. According to the study results, three final obtained factors explained 61.93% of the total variance; this variance reflects the proper and appropriate selection of the questions.  In addition, there were statistically significant differences between marital status and offending attitude domain; between job and education and offending attitude; and security and treatment domains.
Conclusion: The current questionnaire has a high validity and reliability and is also appropriate for the context of Iran.  The attitude of the studied participants was a bit towards using coercion in treatment of mentally ill patients. Therefore, it is recommended that authorities take some steps toward changing health services providers' attitude of using coercion.