This paper describes the development of modelling tools to simulate the effects of agricultural policy changes in New Member States (NMS) of the EU. Partial equilibrium models, developed as part of the AG-MEMOD (Agricultural Member State Modelling) Partnership, are used to simulate the effects of EU Accession and CAP Reform for countries that have recently joined and countries that may soon join the EU. Results show the effect of policy change scenarios on the main agricultural product markets such as grains, oilseeds, livestock and livestock products, as well as other significant components of agricultural output. Estimates can be provided for each year to a 10-year horizon. In the paper, the challenges faced in building agricultural policy models for economies, which have only recently completed the transition to a market basis, are described, along with some illustrative examples of key results. The development of these models for the NMS is a step towards their integration, on a more formal basis, with sister models which have already been developed for the EU15 Member States.