A survey of the roots and nature of conflicts in the Horn of Africa is offered to determine the extent and form of their cross-border or interregional dimensions. In southern Africa, up to the end of apartheid, most conflicts could be related to the struggle for liberation and the strategies of the apartheid government to resist change, even though these external promptings interacted with various internal cleavages. By contrast, almost all conflicts in the Horn of Africa since the 1970s could be said to have primarily internal origins, but they were amplified by a pattern of 'mutual intervention'. Each government sought to deal with ifs own internal conflicts by some degree of support for insurgencies in neighbouring states. This pattern was reversed by a brief period of detente from 1991-94, but then resumed and is likely to intensify with the current Ethiopia-Eritrea conflict. Considerations in promoting regional stability are explored, including in particular, the role of regional bodies in combining economic cooperation, peace making and security roles.