Penan and Berawan indigenous communities have customary access rights to hunt animals and collect forest products at Gunung Mulu National Park (GMNP) to sustain their livelihood. However, their level of knowledge on the types of animals and plants that are allowed to be hunted or collected is a question that needs to be addressed. A poor knowledge of these threatened species might cause the extinction of these vulnerable species. Therefore, this study aims to examine the Penan and Berawan level of knowledge on threatened native animal and plant species in GMNP. A validated pictorial questionnaire was distributed to these 67 communities who lived at Kampung Sungai Melinau, Kampung Batu Bungan, Kampung Long Iman and Kampung Long Terawan using a face-to-face approach. They were asked to identify the native species that needed to be conserved. Most respondents (98.51%) had poor knowledge (mean score, 26.46%) about local threatened species even though they lived close to a UNESCO World Heritage Site. This may be due to lack of exposure to these species in the community. Thus, the findings of this study attempted to explore the situation from the bottom level which portrayed the lack of environmental awareness programmes being implemented in GMNP. It is suggested that the relevant stakeholders should emphasize on species knowledge among the community so that the existing policies can be enhanced and work towards biodiversity conservation.