- The Persian fallow deer (Dama mesopotamica) reintroduction project of the Israel Nature and Parks Authority is based on a permanent breeding core (Hai-Bar Carmel) established in Israel in 1976 from 2 males and 5 females, before the formulation of the guidelines for reinstruction by the IUCN, with no strategic long-term planning, and little consideration of conservation principles and monetary consequences. By the mid 1990s the breeding core had nearly 50 adult females and it became evident that a reintroduction program should be prepared. The existence of a permanent breeding core offered flexibility in protocol and the possibility of a long-term approach based on multiple releases. Using a maximum sustained yield approach, IUCN criteria, and simulations of population performance we formulated a release strategy and a time frame for the project, based on repeated releases carried out sequentially in three reserves in northern Israel with good corridors connecting them. The project began with releases in the Kziv reserve with continuous post-release monitoring and an adaptive management approach. Reproductive success was dampened during the initial years after release, but increased to expected levels thereafter. Survival was higher than expected. Animals from later releases used formerly released animals as cue and established a home range faster. Annual home-range dynamics and social structure were comparable to other similar deer species. The deer transported viable seeds of many species by ingestion (endozoochory) and thinned the forest canopy allowing for better understory growth. Simulations based on empirical data indicated that pre-project demographic simulation offered reliable projections. A growth model incorporating the empirical data on dynamics, habitat preferences, and social structure during the first 2.5 years enabled the construction of a spatially realistic individual-based population model that reliably projected the numerical and spatial growth of the population over a 5-year period. This model was then used to assess future risks due to human sprawl. Due to agricultural damage, the project was forced in 2003 to select a new less favourable site in the Judean hills (central Israel) with no habitat linkage to the former location. Release in this area was based on individuals from the Hai Bar Carmel and from a second breeding core established in the Jerusalem Biblical Zoo. The less favourable site and behavioural problems of the zoo animals hampered the success of the reintroduction. In 2010 the northern region of the Israel Nature and Parks Authority approved a second release site in the Galilee. Using the spatially realistic model described above we reassessed the multiple-site approach, considering options of releases in 1–10 sites carried out in parallel or sequentially. These simulations indicated that the best results, in terms of numerical growth and spatial expansion, would be obtained by repeated releases in two sites carried out sequentially. Computer simulations combined with a permanent breeding core enabled robust planning and an adaptive management approach. Post-release monitoring provided important data for assessing reintroduction procedures and for future management of the species. This reintroduction has greatly enhanced the survival prospects of the Persian fallow deer, and their reintroduction has reestablished important ecosystem processes.