This working paper deals with the question how international trade can lead to economic growth. Since only technical progress can lead to sustained economic growth international trade has to accelerate the rate of technical progress to promote economic growth. Technical progress is mainly generated by the production and the use of ideas. It can be shown that international trade fosters the production of ideas in industrialised countries and that it enables the use of ideas in developing countries. Therefore international trade can promote growth at least in the short run. This is demonstrated via theoretical models and empirical evidence as well as a separate empirical analysis concerning the variety of imported capital goods.