The undertaking was carried out by the Pu Huong Nature Reserve’s management board in coordination with the Centre for Rescue, Conservation and Development of Creatures at the Cuc Phuong National Park. Eight rhesus macaques (Macaca mulatta) and three stump-tailed macaques (Macaca arctoides) were transferred from Cuc Phuong National Park. Both species are classified as rare and endangered under a Vietnamese Government decree. They are also listed in Vietnam’s Red Data Book and the International Union for Conservation of Nature Red List. All the released monkeys were fully grown, healthy, free of infectious diseases, and uninjured. The reserve, home to a variety of wildlife species, including the two macaque species, provides a suitable habitat for the monkeys to adapt, reproduce, and integrate into the existing groups without disrupting the ecological balance./.