In recent years, global conservation organizations have recognized the need to combine in situ and ex situ conservation to protect species, a recognition that has been articulated in various international conventions and declarations. The ongoing decline in species diversity crosses taxa, and deer (family Cervidae) are no exception. However, ex situ conservation of deer faces some challenges that most taxa do not, but also offers some unique opportunities. Veterinary restrictions on the international transfer of deer pose a major challenge to the genetic and demographic ex situ management of deer, while lack of historical records, changing taxonomy, lack of awareness of their conservation status, and low popularity among zoo visitors also hinder ex situ conservation. On the other hand, the fact that some deer species are commercially important provides various opportunities for their ex situ conservation, either by using knowledge and expertise developed for the deer farming industry or by pooling the financial and spatial resources of both the conservation and farming industries. Further opportunities lie in improving cooperation with zoos in range countries, or highlighting the ecological role of deer as prey for large, threatened, popular carnivore species. Understanding both the challenges and the opportunities may lead the ex situ conservation community to improve its deer conservation efforts and allow it to better implement them and ensure the survival of deer diversity in the future.