Background In May 2001, we, scientists from six countries in southern Africa, formed the Environmental Long-Term Observatories Network of Southern Africa (ELTOSA). Further development was made at the ELTOSA conference on Inhaca Island, Mozambique, during July 2002. ELTOSA connects country Environmental Observatories Networks (EON), the African adaptation of LTER (long-term ecological research). The International Long-Term Ecological Research Network (ILTER) has accepted ELTOSA as a regional member, and currently three ELTOSA country members have individual ILTER membership (Namibia in 1999, Zambia in 2001, South Africa in 2002) and others are working towards membership. This position paper describes the development of a vision for EON in southern Africa. We outline the importance of developing EON and list the opportunities this offers for the natural and social sciences. Finally, we focus on some challenges that accompany the development of EON in the region, with suggestions on how to meet them.