Large ungulates across South-east Asia have been experiencing a rapid decline in recent decades because of overexploitation by humans. An absence of reliable data on the abundance and distribution of ungulates makes it difficult to assess the effectiveness of conservation efforts to recover their populations. As the principal prey for Endangered tigers Panthera tigris, depletion of wild ungulates is a major threat to the species' persistence and recovery across its range. This study estimated abundance and distribution of five ungulate taxa using a grid-based occupancy survey across a 3,000 km2 core zone within the 5,950 km2 Nam Et–Phou Louey National Protected Area in northern Lao. The results show an abundance index of 5.29 ± 0.30 ungulates per km2, with muntjac Munticus spp. and wild pig Sus spp. being most common, moderate levels of serow Capricornis milneedwardsii and sambar Cervus unicolor but few gaur Bos gaurus. This low abundance of medium- and large-sized ungulates at the site strongly suggests that strict control of hunting of these ungulates is important for securing their long-term survival as well as that of the tiger population that depends on them, which is currently the only known breeding population remaining in Indochina.