The economic take-off put MERCOSUR in the attention of the main world countries, but it could not avoid showing that the setting up process of the common market for January 1, 1995 was not accomplished.

Starting January 1, 1995 the imperfect customs union was established, which supposed the elimination of all tariff and para-tariffs barriers to the reciprocal commerce and the adoption of an external common tariff for other countries. This aspect is not fully in force at present. The four member States have just signed what is known as "adjustment regime " by which some products in the intra-MERCOSUR commerce would continue paying tariffs for some time. In the same way, the exceptions lists were established to the external common tariff for a group of specific products.

It is planned that the customs union fully governs the four countries starting 2006, while the exceptions lists to the external common tariff and the adjustment regime will be automatically adjusted.

The organizational chart of MERCOSUR was completed with the aggregate of a Commerce Committee aimed at carrying out a follow-up in real time of all the commercial problems that would arise, and on the other hand, be searching for solutions. Its importance and effectiveness was fulfilled to the extent that it was unnecessary to use the mechanism of controversies settlement signed in Brasilia. However, it overloaded the governments with negotiations about problems that needed some political decisions to be solved. An Administrative Secretariat was also created. It is settled permanently in Montevideo.