This paper evaluates research on herbaceous tropical forage legumes in sub-Saharan Africa and offers two alternative explanations for the lack of adoption of adapted species. There is a considerable volume of literature from sub-Saharan Africa on the evaluation, chemical composition, fertiliser requirements, persistence, management and use of forage legumes. Most legumes tested are exotic and emphasis has been placed mainly on Australian species and cultivars of Stylosanthes, Centrosema, Desmodium, Lablab and Macroptilium. Research programmes have been characterised by cycles of introduction and re-introduction of legumes, and most of the screening has been observational or conducted under cutting on-station. Relatively few accessions of a given species have been tested at any one time and, in total, represent only a small proportion of the collections held in the major forage gene banks. Ignorance of the literature and a failure in communication between forage scientists, even within countries, have resulted in costly duplication of effort. Despite the potential benefits of forage legumes and the availability of species adapted to a wide range of environments, actual use in the livestock sector has been limited, with the exception of dairy production systems in highland areas,