Koonamore Vegetation Reserve was established on an overgrazed section of arid vegetation in the north-eastern district of South Australia, in July 1925. It was fenced to exclude sheep and rabbits, or so it was hoped. This paper discusses the regeneration of perennial vegetation since that date. The species common on the Reserve (trees- Acacia aneura, Casuarina cristata, Myoporum platycarpum, Heterodendrum oleifolium, Eucarya acuminata; tall shrubs-Eremophila sturtii, E. scoparia, E. longifolia, Acacia burkittii, Cassia nemophila, C. sturtii; low shrubs-Atriplex vesicaria, A. stipitata, Kochia sedifolia) are characteristic of large areas of arid southern Australia. Little or no regeneration of most of the tree and shrub species has occurred in unprotected areas. Many stands are showing obvious signs of senescence and many trees have died. Rabbits appear to be a major problem hampering regeneration. However, stands of Atriplex spp. in paddocks adjacent to the south and east sides of the Reserve have provided a seed source for effective recolonization of some denuded areas within the Reserve. The regeneration of Cassia spp. has also been spectacular in some places. Problems in regeneration and fluctuations in numbers of perennial species are discussed in relation to community dynamics, range management, and soil erosion.