The Common Agricultural Policy (CAP) is moving away from coupled payments towards an increasing emphasis on decoupled payments. However current CGE models to study effects of decoupled payments remain limited. This paper introduces the application of a CGE model framework for a comparative analysis of possible effects caused by coupled and decoupled support on agricultural and food sectors in an economy. The CGE model used is the STAGE_AGR which is an extension of the STAGE model containing equations that permit modellers to introduce different system of decoupled payment representation. We have taken as empirical example the case of Ireland for modelling agricultural payments either as fully or partially decoupled.