The expansion of Prosopis juliflora (hereafter Prosopis) has been a serious problem in Sub-Saharan Africa, including in several of the countries of the Intergovernmental Authority on Development (IGAD) region - Djibouti, Eritrea, Ethiopia, Kenya, Somaliland, and Sudan. The species crosses borders and affects entire ecosystems - the environment and natural resources upon which the pastoral, agro-pastoral communities, as well as many peri-urban communities, depend. Prosopis was introduced to the Horn of African countries for various reasons, but in most cases without preliminary long-term impact studies. Prosopis and the challenge it is posing has become a serious issue in the most IGAD countries, affecting the livelihoods of farmers, agro-pastoral and pastoral communities. It has taken over farm land, browse and pasture, as well as reduced the water supply for people and for livestock in affected areas. Some governments have opted for expensive physical eradication methods which, however, are not proving effective. Others are trying alternative approaches which consider Prosopis as an underutilised resource, rather than just an ecological menace. In 2007, with financial support from Oxfam Novib, PENHA undertook an initiative pursuing this alternative approach. Working with the Animal Production Resource Centre (APRC) of Sudan, PENHA conducted action-oriented research, and subsequently used the evidence obtained to successfully conduct a pilot project.