The lost caravan of Ma’den Ijafen, Mauritania, with its cargo of cowries and brass, is widely discussed in African archaeology, providing significant insight into the nature of long-distance trade in the medieval period. While the brass bars recovered by Théodore Monod during his expedition to the site in 1962 have received considerable attention, the cowrie shells described in his comprehensive publication of the assemblage in 1969 have received much less coverage. This issue was addressed during a recent visit to the Institut Fondamental d’Afrique Noire (IFAN) in Dakar, Senegal in May 2017, when the authors re-examined the shells as part of a wider project which also involved archaeological and environmental surveys in the Maldives, the oft-assumed source of these shells. Examinations of natural history collections of cowries, ethnographic interviews in the Maldives, and environmental surveys in East Africa were also carried out. Drawing on insights from these surveys, we systematically compared the Ma’den Ijafen cowrie assemblage to three others from the Maldives, focussing on four criteria: species composition and diversity, shell size and evidence of modifications. This analysis enabled us to shed new light on the nature of the Ma’den Ijafen cowries and their wider significance to understanding the role of the shells in West African trade networks.