Newadayes, preventing and/or mitigating unfavorable consequences of increasing vulnerability of forest ecosystems is became as one of the most important goals of natural resources managers in all over the world. Achieving this goal requires use of methods, which can provide scientific and on-time decision making for managers. Among these methods, Delphi method and Fuzzy Analytic Hierarchy Process (FAHP), due to scientific validity and applicability at different multidisciplinary levels, are appropriate for decision making in complex condition and in confrounting to multiple criteria. In this study, both methods were used for prioritizing the multiple negative factors (stresses and disturbances) affecting on mangrove forests. Results showed that regarding to current status of mangrove forests of Iran, anthropogenic stresses and disturbances generally have more importance than other negatively effective factors; so, pollutants emision and engineering interventions in coasts were placed in the first and third priority in the final ranking, respectively. Results also showed that among various climatic effective factors, sea level rise has higher importance than other factors (placed in the second rank). Ofcourse, other scientists in the other parts of the world also expressed that sea level rise is one of the most important climatic factors affecting on current and future decrease of area and health of mangroves in all over the world. Results of the this study could be used as decision making supporting tool and play an important role in efficiency and success of sustainable planning and management of mangrove forests in Iran and other mangroves of the coastal areas of Persian Gulf.