Commercial advertising is the main tool for marketing goods and services offered by businessmen in the market due to the easy access to final customers and its capacity to influence their purchase decisions. Norms on advertising are directly related to those on unfair competition. For this reason, the European Union, aware of its importance for the development of internal market, has created a number of norms to regulate commercial advertising and to eradicate all ads that may imply unfair actions that can irregularly alter the market and indiscriminately affect competitors and consumers. Spain was required to transpose community regulatory provisions to its national law; compliance with this requirement involved significant and complex modifications of the existing advertising system.