This article presents a legal and economic analysis of Latin American integration and concludes that legal integration can be explained by the degree of overlap found in the economic structures of the countries in a trade agreement. More specifically, it argues that larger proportions of bilateral intrasectoral trade stimulate the private sector's demand to harmonize trade-related laws. It also demonstrates that countries with emerging high-growth sectors will tend to harmonize their laws with those of countries experiencing the same changes in their economic structure, whereas traditional agrarian economies do not have an incentive to enter harmonization agreements that benefit high-growth sectors. In this respect, countries with similar complexity in their legal systems will seek to harmonize their laws. Copyright 1998 by The Policy Studies Organization.