Abstract: May 1999 - Preferential trade agreements that are limited to the elimination of tariffs for merchandise trade flows are of limited value at best and may be as easily welfare-reducing as welfare-enhancing. It is important that preferential trade agreements go beyond eliminating tariffs and quotas to eliminating regulatory and red tape costs and opening up service markets to foreign competition. Deep integration-explicit government actions to reduce the market-segmenting effect of domestic regulatory policies through coordination and cooperation-is becoming a major dimension of some regional integration agreements, led by the European Union. Health and safety regulations, competition laws, licensing and certification regimes, and administrative procedures such as customs clearance can affect trade (in ways analogous to nontariff barriers) even though their underlying intent may not be to discriminate against foreign suppliers of goods and services. Whether preferential trade agreements (PTAs) can be justified in a multilateral trading system depends on the extent to which formal intergovernmental agreements are technically necessary to achieve the deep integration needed to make markets more contestable. The more need for formal cooperation, the stronger the case for regional integration. Whether PTAs are justified regionally also depends on whether efforts to reduce market segmentation are applied on a nondiscriminatory basis. If innovations to reduce transaction or market access costs extend to both members and nonmembers of a PTA, regionalism as an instrument of trade and investment becomes more attractive. Using a standard competitive general equilibrium model of the Egyptian economy, Hoekman and Konan find that the static welfare impact of a deep free trade agreement is far greater than the impact that can be expected from a classic shallow agreement. Under some scenarios, welfare may increase by more than 10 percent of GDP, compared with close to zero under a shallow agreement. Given Egypt's highly diversified trading patterns, a shallow PTA with the European Union could be merely diversionary, leading to a small decline in welfare. Egypt already has duty-free access to the European Union for manufactures, so the loss in tariff revenues incurred would outweigh any new trade created. Large gains in welfare from the PTA are conditional on eliminating regulatory barriers and red tape-in which case welfare gains may be substantial: 4 to 20 percent growth in real GNP. This paper-a product of the Development Research Group-is part of a larger effort in the group to analyze regional integration agreements. The authors may be contacted at bhoekman@@worldbank.org or konan@@hawaii.edu.