The author investigates the European institution attention to migration flows from the 1950s to the 1970s and underlines the social and economic problems relating to the arrival of people with a different language, religion and habits in most of the European Community countries. During the Golden Age the inconveniences were clearly less significant than the advantages: migrants represented one of the most relevant factors favouring the excellent results of the European Common Market. Only in the 1970s, when the two oil shocks strongly reduced occupation in Western Europe, the problem of immigrant workers became important and measures limiting immigration in European countries were introduced. As a result, the real status of migrants (an economic resource or social problem) depended on economic trends and only to a residual degree on cultural differences.