The linkage between El Nino variability and rainfall over southern and east Africa is well known and has been explored by many workers in the past. Basically this relationship is characterized by a "dipole" pattern with tendency for lower than normal rainfall over much of southern Africa and above normal rainfall over low latitude eastern Africa during warm episodes. Also well known is the linkage between Indian Ocean SSTs and El Nino activity, with warm episodes being generally accompanied by higher than normal SSTs in much of the western and central tropical Indian Ocean. Because of the major socio-economic impacts of rainfall variability in southern and eastern Africa, prediction of precipitation in that region is of special concern for climate forecast activities. It is thus important to understand whether the relationship between rainfall in southern and eastern Africa and El Nino activity represents a true teleconnection forced directly by changes in tropical Pacific SSTs, or whether the association is mediated by changes in Indian Ocean SSTs. Extended ensemble experiments with an AGCM have been performed in which time-varying SSTs were prescribed a) globally, b) in the Pacific Ocean only, and c) in the Indian Ocean only. The results of these simulations are clear in showing that the link between southern and eastern African summer rainfall and El Nino activity is driven primarily from the Indian Ocean. These findings emphasize the fact that accurate predictions of rainfall in southern and eastern Africa will require accurate forecasts of Indian Ocean SSTs