This article concerns the corporate responses to the economic integration process from 1973 to 2008 in two small, open European countries, Denmark and Sweden. It focuses on strategic relations regarding the integration process and analyses the changing diversification patterns and internationalisation levels. The hypothesis from the economic integration literature indicates that we could expect a high degree of core business focus combined with a high degree of internationalisation concurrently with the economic integration process. The Danish case confirmed this prediction in a clear and substantial way, while the Swedish diversification pattern was marked by the continuous importance of diversification in the period from 1973 to 1993. This confirms the findings of Whittington and Mayer, who investigated the development of the largest British, French and German manufacturing enterprises. But the result also indicates that diversification perhaps proved to be less important after 1993 when the process of ‘Europeanisation’ dynamics was succeeded by the globalisation processes including the fast growing economies in South East Asia.