The International Livestock Research Institute (ILRI) is widely regarded as a global center of excellence for livestock-related development research. This chapter questions the notion of excellence by tracing the history of ILRI back to its conception as two separate centers: the International Laboratory for Research on Animal Diseases (ILRAD) and the International Livestock Centre for Africa (ILCA). It examines why ILRAD and ILCA were established as two distinct research centers and explores the impact this had on the conceptualization of human–livestock relationships, livestock diseases, and research excellence by CGIAR in sub-Saharan Africa. The chapter also presents two contemporary case studies – one examining the development of transgenic, trypanosome-resistant cattle, and the other exploring the establishment of CGIAR Research Programs (CRPs) and their impact on agricultural research for development – to show the ways in which ILRI’s unique history continues to shape and affect its current projects. The chapter emphasizes the importance of recognizing the ways in which excellence is conceptualized and reflecting on the implications this has for research and development.