The regional economic blocks among OIC countries play an important role in economic improvement for these countries. The paper provides recommendations and policy options for establishing an Islamic common market. These recommendations will be derived from assessing the success and failure of the existing preferential trading agreements and regional economic groupings among the OIC countries. Also, the paper assesses trade potentials among the OIC member countries. To achieve these objectives, the paper estimates a gravity model of trade creation and diversion among the various economic blocks of the OIC member countries