Iron Age sites associated with the Toutswe tradition in Eastern Botswana date between CE 700–1300 and share a variety of settlement patterns, economic features and material culture. The presence of domestic fauna, settlement structures and concentrations of vitrified dung provide archaeological evidence for herding economies. However, due to factors of preservation and past retrieval techniques, evidence for plant remains is still somewhat limited for the Toutswe sites in Botswana. Additionally, archaeological remains such as flora, fauna and material culture often provide only indirect evidence for their contributions to diet. This study provides new evidence for the diet of individuals from the Toutswe tradition. Given the large numbers of animal remains and residues at Toutswe sites, the expectation is that animal domesticates were also an integral part of the diet. Stable isotopic analysis of human remains indicates that even though domestic cattle and sheep occur in great abundance at Toutswe sites, their contribution to the diet may be minimal. The main source of protein for individuals at Kgaswe and Taukome comes from C4 plants such as sorghum and millet and to a lesser extent, animal products. The practice of maintaining large domestic herds for economic and social reasons rather than for primary subsistence in southern Africa today may have its roots in the Iron Age populations of the region. Copyright © 2010 John Wiley & Sons, Ltd.