This article examines the economic organization of the trans-Saharan slave trade between the fourteenth and nineteenth centuries on those routes that moved slaves from Sudanic Africa via entrepôts in the Sahel and Sahara to the Maghrib. The commercial framework of this trade was integrated into ethnic, cultural, and religious systems, yet for its efficient operation could not rely solely on these social institutions. Temporary cooperation of itinerant slave traders is considered and then projected onto the broader patterns of commercial organization. It is shown that similar pressures resulted in comparable outcomes: partnerships were formed to take advantage of economies of scale in commercial services and to limit cooperation problems. This demonstrates that the organization of the trans-Saharan slave trade was economically rational and can be analysed in terms of cooperative and non-cooperative strategies. Moreover, it is argued that the trade was not restrained by social institutions but versatile in adapting its economic institutions to specific market imperfections. It is concluded that recent economic models are more useful in explaining the economic behaviour of slave traders than conventional neoclassical economics.