Thispaperproposesadecentralizedoutputfeedbackcontrolschemeappliedtotwo-areainterconnectedpowersystem.ThecontrollersynthesisproblemisformulatedasthescaledH∞controlproblemandanewLMI-basedalgorithmisproposedtocomputethedecentralizedcontroller.TheproposedcontrollerprovidesrobustnesswithregardtoparametricuncertaintiesandalsoattenuatesboundedexogenousdisturbancesinthesenseofL2-gain.Simulationresultsclearlyshowtheeffectivenessofdevelopeddecentralizedoutputfeedbackcontrolscheme.