The Iraq-Mediterranean oil pipeline was one of the most extensive and costly pipeline construction enterprises of its time. Built by the Iraq Petroleum Company (IPC) between 1932 and 1935, it consisted of two 12-inch trunk lines 1,150 miles long that ran from the oilfields of Kirkuk to Haditha where it bifurcated, with one branch taking a northern route through French Syria to Tripoli, Lebanon, and the other running south through British mandated territory to Haifa, Palestine. With a joint transit capacity of 4 million tons per annum, the completion of the line marked the beginning of Iraq’s role as an oil exporter in the region. This paper examines the political, commercial, and technical controversies that were involved in the planning of this pipeline. In particular, it focuses on the dispute that arose over the pipeline’s alignment and the means by which it was resolved. After its completion, such controversies could be “black boxed” and made invisible, as the pipeline became an accepted fact of the physical, political and economic landscape of the region. However, the pipeline’s ultimate form – a bifurcated line to two points on the Mediterranean coast – was the result of lengthy diplomatic and commercial negotiations between the oil company, Iraq, the three transit states, and mandatory powers, Britain and France, in addition to technical surveys, reports, and calculations, the validity of which was repeatedly questioned and debated by IPC board members. Drawing on material in the British, French and IPC archives, this paper examines how the alignment of the pipeline first emerged as problem in the course of concessionary negotiations between the IPC and the Iraq Government, before turning to consider how the dispute was resolved and the ways in which it shaped the various actors involved. The paper pays particular attention to the mobilization of technical knowledge and expertise in the dispute. It argues that a division between the technical/ commercial and political/national interests was being continually produced and invoked by various actors in order to further their goals. This process was an important factor in enabling the IPC to establish and maintain an identity as a commercial entity and to make claims to a non-political status, which in turn shaped its relationship to state actors and institutions. In this way, an examination of the pipeline sheds light on broader questions relating to the formation of institutional identities and the relationship between corporations and governments.