Recent studies have suggested that large firms diversify their technological competencies through a cumulative learning process oriented both to augmentation in new fields as well as to exploitation in new markets, the corporate networks created for this purpose justifying the expression "globalisation of innovation". Given the international dispersion of the creation of new technology within multinational corporations (MNCs) and their consequent change of innovatory strategies, the analysis of the relationship between the diversification and internationalisation of their technological activities seems to increasingly call for a contextual account of the locational issues associated with accessing capabilities and locally specific sources of innovation external to the firm. The purpose of this paper is thus twofold. First, it reviews the relationship between the diversification and internationalisation of technological activities by large firms historically and more recently, and to show how their closer association is bound up with the recent formation of internationally integrated networks within firms; secondly, it proceeds to investigate more thoroughly the geographical spread of such MNC networks within Europe, whether formed by European-owned or non-European-owned firms, paying particular attention as to the relative attractiveness of locations for the technological development of foreign-owned firms, at a sub-national regional level within Europe.