Greece has applied for membership in the European Communities on June 13, 1975, Portugal on March 28, 1977, and Spain in the same year on July 28. With the treaties signed in the meantime Greece has become the tenth member country since January 1, 1981, while Portugal and Spain have become the eleventh and twelth member since January 1, 1986. However, the routes of these countries to the EC were much longer. The aim of the study is to overview the experience of Greece, Portugal and Spain with their accessions to the European Communities (EC) and to formulate various conclusions and recommendations for Poland where the association agreement with the EC is treated as a specific vehicle to full membership in the Communities. Of particular interest are the economic liberalization, macroeconomic policy and economic performance of the Three till the end of the 1980's. Respective aspects are compared and discussed. With regard to economic performance the results achieved by the whole EC-12 are additionally treated as reference points. Then follow the lessons for Poland.