Abstract: The increase of nature reserve areas in the country is Insufficient to conserve biodiversity. The study aims to evaluate the management effectiveness of seven nature reserves in the Sultanate of Oman. The study used the Rapid Assessment and Prioritization of Protected Area Management Methodology (RAPPAM) tool. The tool examines the management cycle elements of the nature reserve includes; context, planning, input, process, and outputs. Also, the tool is used to evaluate the pressures and threats that nature reserves suffer from.