Oil is one of the most widespread high-density energy sources in the world: its importance for the military-industrial complex became even more evident in the postwar context. In this framework, establishing the conditions for accessing the world's oil-rich areas became essential for states, not only to provide for their own energy needs, but also to buttress national economic and geostrategic interests, and protect energy security. In addition, regulating the oil flow between countries afforded the ability to influence their operational capabilities. Exploiting oil as a geopolitical weapon was not distinctive of the two global hegemonic powers, but was also employed by less powerful countries, such as France and Italy. My thesis shows how, from the second half of the 1940s, successive Italian and French administrations established agencies for hydrocarbon management, and devised strategies of oil exploration according to their political agendas. Achieving energy autonomy was the main objective of both countries. However, the predominance of Anglo-American interests in both French and Italian oil scenarios led to continuous bilateral diplomatic tensions, especially over issues of exploration rights. Anglo-American governments and companies sought to shape the French and Italian oil scenes to their benefit, also by looking for allies in the political classes of the two countries. It was the outcome of these 'oily deals' that eventually shaped the history of Italian and French oil industries.Conflicting interests were revealed at their fullest during the Algerian war of 1954-62: following the discovery of large oil and gas fields in Algeria, US and Italian companies started to negotiate, first with the French and then the Algerians, their access to, and prospecting rights for Algerian territories. My work shows that negotiation processes involved secret surveillance activities, the establishment of parallel diplomacies, and serious confrontation between Cold War allies. A fundamental role in these deals was played by technocrats and geoscientists, who facilitated the communication of secret data on oilfields to their national authorities. Significant global oil discoveries occurred worldwide in the 1950s, eventually leading to overproduction: an outcome assisted by major progress in geophysical prospecting techniques. France's new role as an oil producer thanks to discoveries in Africa provoked a shift of national interest from exploration to transport. At the same time Italy, after the signing of massive oil-for-technology barter agreements with the Soviet Union, could now dispose of a surplus that needed channelling to potential outlets. For both countries, building pipelines became an essential aspect: however, as both were targeting the West European market, Europe became an arena of bitter competition for pipeline dominance. Italian-Soviet contracts, together with the current level of West European trade with the Soviet Union, prompted an examination of Western security by international organisations. The issue of limiting Soviet oil exports into West European countries was widely debated at the European Community and Nato, as was European technological aid to the Soviet project of constructing a colossal pipeline system. My analysis of the terms of the debates, their development and outcome, reveals the ambiguity of the concepts of security and 'strategic technology' as a ground for decision-making, indicating how these were construed as co-products of negotiations.