Background: An increased awareness of how people with intellectual disabilities (ID) understand death and dying is necessary in supporting life-long learning, post-bereavement support and planning end-of-life care. Previous research suggests that adults with ID have a limited or "patchy" understanding of the basic biological components of death. However, the relationship between biological understanding of how the body works and conceptualisation of death remains unexplored in this population. Method: Thirty adults with ID were interviewed to assess their knowledge of human body function and their understanding of the concept of death. Using pictures, participants were asked if they recognised certain organs, asked to explain the function of various body parts and what would happen if certain body parts were missing or did not work. Participants who referred to 'life' or 'not dying' as the goal of body function were categorised as "Life Theorisers." In addition, participants were asked about the causes of death, whether all things die and the status of the body after death. Results:: The results support previous studies suggesting that understanding of death in adults with ID varies from partial to full comprehension and is associated with level of ID. Also, death comprehension was positively correlated with total body interview scores and "Life Theorisers" who understood that body parts maintain life and who spontaneously appealed to "vitalistic" concepts when reasoning about the human body were also more sophisticated in their understanding of death. Conclusion: The study highlights the relationship between knowledge about the goal of human body functioning and death comprehension in adults with ID. The potential that learning to adopt a "vitalistic" approach to human functioning may have on the acquisition of a greater understanding of death and dying, understanding illness and supporting end-of-life planning is discussed.