The present paper proposes a novel energy management system in islanded microgrids which considers static frequency. Microgrid frequency continuously deviates from the nominal value, subject to the unpredictable renewable and/or load variations. The small capacity and low inertia stack of the utilized inverter-based distributed energy resources intensify the importance of incorporating the frequency into the microgrid energy management system. Motivated by this need and owing to the direct coupling between the frequency and reserve scheduling, energy and reserve resources of an islanded microgrid are aimed to be scheduled such a way the frequency be managed securely. In this regard, first, the frequency dependent behavior of droop controlled distributed generations should be modeled in detail. Next, microgrid central controller can schedule the reserve resources in order to satisfy both economical and security issues by modification the reference power settings. Simulation results in a typical microgrid and over a daily period verify the effectiveness of the proposed frequency aware energy management system.