The use of trademarks in competitive markets has been partially neglected by the economic literature. The increased availability of official statistics currently permits to conduct empirical analyses and explore several themes. Trademarks may be interpreted as a form of product differentiation, since they are the first and most important cause of the perception of differentiation by consumers. Using this approach, the intensity of trademarking activity is a proxy of the relative degree of horizontal product differentiation within an economic sector. Empirical observations show that, in the major European countries, product differentiation and export specialization are positively associated, as predicted by the combined interpretation of distinct theories of international trade and endogenous growth. Trademark statistics may also provide information regarding the average quality within each sector, and this is useful to explain some inconsistencies between export and trademark specialization.