When an area is brought under protection, current animal populations and their habitat preferences need to be assessed to predict population trends and future habitat availability. Using data from walking transects, we estimated the size of native ungulate populations on an abandoned cattle ranch in a coastal savannah in Tanzania, now included in the new Saadani National Park. Data were analysed with distance sampling and conventional strip transect techniques and were compared with results of previous wildlife counts. Few individuals of mainly browsing species were present in former cattle grazing areas exhibiting high bush-encroachment while a ten times higher biomass of browsers and grazers was found in the cattle-unmodified savannah. Population sizes of some species increased twofold between 1991 and 2001 within the entire area but neither population size nor species richness increased in the abandoned rangeland during our 3-year study period from 2001 to 2003. We conclude that the former ranch has potential for future recolonization by wild ungulates. Resettlement will take place gradually with ‘pioneer-species’ facilitating the entry of more demanding species. Habitat restoration through wildlife can be observed and quantified on Mkwaja Ranch which will be of importance for future management of native ungulates reclaiming abandoned rangeland.