The underlying theme of this article is that to understand the process of European integration, it is vital to understand the dynamics of the European policy-making process and the crucial role of the European institutions within this process. In this article the internal dynamics of the policy-making process within the European Commission in two directorates (DG V [Employment, Industrial Relations and Social Affairs] and DG XIII [Telecommunications, Information Industries and Innovation]) are explored. It is argued that a vital characteristic of the Commission's ability to influence any policy sector is its ability to respond rapidly to any 'windows of opportunity', ripe for EU intervention, or indeed to facilitate the appearance of these windows. Yet, the means required to achieve this end, and the degree of success met, vary from sector to sector. If it is accepted that the Commission has an important role to play in EU policy-making, and ultimately in the integration process, a better understanding of the functioning of its constituent parts, of the interrelationships between them, and of the influence of their activities upon the actions of the Commission as a whole, is vital.