The Large-antlered Muntjac is native to Laos and Vietnam (and possibly marginally in Cambodia) where it is largely restricted to the Annamite Mountain range. Its current occurrence across this range is uncertain, and the global population is scarce and scattered in isolated populations, which, in Vietnam, are all small or have recently faced local extinction. Since the remarkable scientific discovery of the species in 1994, there have been no project specifically focusing on the species. The species was up-listed from Endangered (2008) to Critically Endangered in 2016. Its global conservation status has been assessed based on the few post-2000 (direct or indirect) records across its geographic range compared to record rates pre-2000; evidence-based declines in the most healthy populations; the considerable increase in commercial and recreational wildlife hunting in the species’ range; the considerable reduction in suitable habitat for the species and the fact that the species is associated with mainly lowlands, which are systematically in close proximity to human settlements, where hunting for local consumption and trade has increased in the past decade. These compiled evidences have led to the conclusion that the Large-antlered Muntjac’s global population has faced a decline of over 90% in the last 20-30 years, and will continue to decline at the same rate until total extinction if no urgent action is taken to reverse current trends. The chore global population of the species (which has already experienced important declines) occur in Laos and notably in the Nakai-Nam Theun National Protected Area (NNT NPA), where it is imperative to act now to ensure a sustainable population. This project aims the population in NNT NPA to develop Conservation Action Plans at the global scale.