One of the major obstacles to the success of the programs and goals of the organization is lack of information, lack of confidence and existence of organizational silence. organizational silence can cause complications such as damage to the mental health of employees. Accordingly, this study explores the relationship between organizational silence and mental health of the stuff. This study in term of purpose is applied and in term of method is descriptive-correlation research. Population of this study was the workers of department of Water and Wastewater of East Azarbayjan province (926), that 283 of them were selected based of Morgan and Krejcie table and randomly and responded to organizational silence questionnaire and general mental health questionnaire. Reliability of the questionnaire has been examined through Cronbachs’ Alpha coefficient and their validity was confirmed through content validity review. Data were analyzed using structural equation modeling. The obtained results indicate a significant relationship between organizational silence and its components (Acquiescent, Defensive and Prosocial) with mental health of staff.